Methods and apparatus for detecting compounds in liquids

ABSTRACT

Described herein are apparatus and methods for detecting substances of abuse or other analytes in liquids. For example, the apparatus and methods described herein can be used for real-time detection of analytes, such as substances of abuse. The methods comprise providing a detection area comprising a chromatographic membrane capable of receiving the liquid and allowing for migration of the liquid, the chromatographic membrane comprising an anti-analyte antibody-particle conjugate, an analyte-conjugate protein at a test line; exposing at least the first location of the apparatus to the liquid; and determining whether an interaction between the analyte-conjugate protein and the liquid occurs to detect the presence of the analyte. The chromatographic membrane may further comprise an anti-species antibody at a control line. Specific buffers are disclosed, and these buffers may be used in the preparation of the apparatus to overcome challenges associated with miniaturization and challenges associated with exposure to beverages.

CROSS-REFERENCE TO PRIORITY APPLICATIONS

This application claims priority to U.S. Provisional Application No.62/287,677, filed on Jan. 27, 2016; U.S. Provisional Application No.62/287,623, filed on Jan. 27, 2016; U.S. Provisional Application No.62/287,643, filed on Jan. 27, 2016; U.S. Provisional Application No.62/337,603, filed on May 17, 2016; U.S. Provisional Application No.62/337,558, filed on May 17, 2016; and U.S. Provisional Application No.62/337,608, filed on May 17, 2016, each of which is incorporated hereinby reference in its entirety.

FIELD

Described herein are apparatus and methods for detecting compounds inliquids. Also described are buffer solutions useful in the apparatus andmethods. For example, the apparatus and methods described herein can beused for real-time detection of substances of abuse.

BACKGROUND

The demand and need for persons to be able to detect differentsubstances on a real-time basis has increased with increased frequencyof drug use and abuse. In some embodiments, a need may arise todetermine if a drug has been added to a beverage without the consumer'sknowledge, and to make this determination discretely.

For example, an increased misuse of various psychotropic and/or sedatingdrugs for recreational or criminal purposes has become more problematicin the present culture. A particularly troubling form of misuse is thesurreptitious introduction of these drugs into ordinary beverages forthe purpose of rendering the consumer of the beverage disoriented orunconscious. The unknowingly sedated individual may then be takenadvantage of, e.g., become the victim of robbery or sexual assault.Drug-facilitated sexual assault has become increasingly common,particularly among younger members of the population, to the degree thatmost universities have warning and prevention programs and policies inplace to prevent drug-facilitated sexual assault. Conventional apparatusto detect such drugs prior to ingestion often are insufficient as theymay be too cumbersome to use, take too long to detect the targetedsubstance, detect only a limited substance, and lack selectivity andsensitivity to many other compounds.

As another example, an increased frequency of diagnoses of auto-immunedisorders or highly sensitive allergies has occurred in the generalpopulation. For example, Celiac's disease, peanut allergies, lactoseallergies or other conditions triggered by different ingested substanceshave become more common in the general population. If the particularharmful substance is ingested by persons having these types ofconditions, significant and severe consequences for the person mayresult.

In view of these trends, conventional testing methods and devices oftenare too cumbersome or take too long to evaluate a particular liquid fora targeted substance. In some embodiments, no specific miniaturizedapparatus for real-time detection of certain targeted substances orcompounds exist. In some embodiments, beverage components may interferewith testing methods.

SUMMARY

The terms “invention”, “the invention”, “this invention” and “thepresent invention” used herein are intended to refer broadly to all ofthe subject matter described herein and the claims below. Statementscontaining these terms do not to limit the subject matter describedherein or limit the meaning or scope of the claims below. This summaryis a high-level overview of various aspects of the invention andintroduces some of the concepts that are further described in theDetailed Description section below. This summary is not intended toidentify key or essential features of the claimed subject matter, nor isit intended to be used in isolation to determine the scope of theclaimed subject matter. The subject matter should be understood byreference to appropriate portions of the entire specification, any orall drawings, and each claim.

Disclosed herein are apparatus and methods for detecting the presence ofa targeted substance, analyte, or drug in a liquid. In some embodiments,the apparatus is a lateral flow device for a lateral flow assay, wherebya liquid to be analyzed migrates along a fluid path from a sample area,across a conjugate area, across a chromatographic membrane, and into awick. The target substance or analyte, if present, reacts with ananti-analyte antibody and the reaction results in a visual indication ofwhether the target analyte is present in the liquid. In some examples,aptamers may be used instead of or in addition to antibodies.

As one example, the methods and apparatus described herein can be usedfor real-time point-of-contact detection of drugs, such as date rapedrugs or other sedating drugs, in beverages or bodily fluids. In otherexamples, the methods and apparatus described herein can be used forreal-time point-of-contact detection of heavy metals in foodstuffs ornutritional supplements; for the detection of contaminants in cosmetics;or for detection of contaminants or nutrients in soils. In someembodiments, the methods and apparatus described herein can be used forreal-time detection of any analyte for which an anti-analyte antibodyexists or may be manufactured.

Accordingly, described here are viable methods and apparatus for thesafe, real-time detection of targeted substances. Examples of suchtarget substances include compounds within abused substances such asdrugs, allergens, and biological and environmental toxins. Non-limitingspecific examples of target substances include benzodiazepines;amine-containing compounds, including but not limited to, narcotics;alcohol; and other abused drugs, e.g., club drugs. Current “club drugs”include ketamine, 4-hydroxybutanoic acid (GHB), ephedrine,methamphetamine, amphetamine, flunitrazepam,3,4-methylenedioxy-methamphetamine (MDMA), also known as ecstasy ormolly, benzodiazepines such as clonazepam, tetrahydrocannabinol (THC),and many more. Drugs that impair memory or sedating drugs such aszolpidem, eszopiclone, ramelteon, zaleplon, doxepine, triazolam,temazepam, and alprazolam may be detected.

Other examples of such target substances include proteins, sugars,steroids and their metabolites. Still other examples of targetsubstances include poisons, pesticides, toxins, chemical warfare agents,environmental poisons, explosives and the starting materials used tomake them. Further, the target substances may include small molecules ormixtures of small molecules. In some embodiments, an apparatus maydetect multiple analytes.

Further, a single-analyte or a multi-analyte apparatus may incorporate asignaling mechanism, which in some embodiments is a visual indication, avibration, or a sound that indicates presence or absence of the targetcompound. For example, the visual indication can comprise theappearance, or lack thereof, of a colored dot, pattern, or region; theprinting of words, such as “SAFE,” “OK,” “YES,” or “NO”; checkmarks;emoticons or symbols such as a “

”; or fluorescence. In some examples, the signaling mechanism comprisescompleting lines, logos, patterns or symbols.

In some embodiments, the apparatus described herein are very small. Forexample, the apparatus may have a length of 20 mm or less, 15 mm orless, 12 mm or 10 mm or less. In some embodiments, the apparatuscomprises a length ranging from about 10 mm to about 150 mm, forexample, from about 10 mm to about 25 mm, or from about 10 mm to about20 mm. In some embodiments, the apparatus can have a length of about 10mm or less, 11 mm or less, 12 mm or less, 13 mm or less, 14 mm or less,15 mm or less, 16 mm or less, 17 mm or less, 18 mm or less, 19 mm orless, 20 mm or less, 21 mm or less, 22 mm or less, 23 mm or less, 24 mmor less, 25 mm or less, 26 mm or less, 27 mm or less, 28 mm or less, 29mm or less, or 30 mm or less In some embodiments, the apparatus has afluid path length greater than the length of the apparatus.

In other embodiments, the apparatus may have other dimensions. Theinvention, however, overcomes the significant hurdles associated withthe miniaturization of lateral flow assay technology. For example,miniaturization can lead to an undesirable increase in the flow rate ofthe liquid across a chromatographic membrane. In addition to challengesposed by miniaturization, some target liquids (e.g., beverages) includeacidic components, high ethanol concentration, high sugarconcentrations, and/or other components that may interfere with accuratetest results. In some examples, the apparatus is miniaturized to beconvenient for discreet use and/or to be wearable. Specific embodimentsof wearable apparatus consistent with the present apparatus and methodsare described and set forth in a PCT patent application entitled“Wearable Apparatus for Detecting a Target Substance in Liquids,”applied for by Undercover Colors, Inc. and filed on the same day as thepresent application, which is incorporated by reference in its entirety.Additional benefits of miniaturization of a lateral flow assay includereduced raw material usage, the ability to pack more assays intoshipping containers, having an increased number of assays multiplexed ina single apparatus, significantly reducing sample volume, and providingrapid test results due to shorter flow distances.

The apparatus and methods described herein overcome challengesassociated with miniaturization and challenges associated with exposureto beverages and other mixtures. In some embodiments, the apparatus andmethods moderate liquid flow rate by modifying the chromatographicmembrane and/or modifying the viscosity of the liquid. In someembodiments, buffer solutions may be used to prepare the apparatus,leaving residual buffer components at desired locations on theapparatus, so that in use the buffer components are reconstituted andneutralize acidic components in a test liquid, slow the progression ofthe test liquid through the device, or otherwise facilitate the testmethod. In some embodiments, buffers or buffer solutions may becustomized for treatment of various components of an apparatus, such asthe sample area, the conjugate area, and/or the chromatographicmembrane.

In some embodiments, the buffer solution can comprise a viscosity of atleast 2 centiPoise (cP). In some embodiments, the buffer or bufferadditives increase the viscosity of the liquid being analyzed, therebyadjusting the flow rate of the liquid across the chromatographicmembrane. In some such embodiments, when residual buffer components onan apparatus are reconstituted by a test liquid, the reconstitutedbuffer solution increases the viscosity of the test liquid and slows theflow rate of the liquid.

In some embodiments, a buffer solution may be utilized in preparingreagents or in applying reagents to the apparatus. In some embodiments,the solution or residual buffer composition may render the testcompatible with liquids that may contain an analyte. In someembodiments, unique buffer components may resolve, bind, or eliminateincompatible substances, such as acids (including alpha-hydroxy acidssuch as lactic acid, malic acid, or citric acid), found in the liquid.In some examples, buffer additives may be introduced to components ofthe apparatus in a buffer solution or by themselves. In someembodiments, the buffer liquid may be evaporated after the buffersolution is applied. In this case, a residual buffer composition is lefton the area of the apparatus that was exposed to the buffer solution.

The sample pad or area, in some embodiments, is the component or portionof the apparatus that is exposed to a test liquid. In some embodiments,a sample pad buffer may neutralize the test liquid when the liquid is anacidic beverage. In some embodiments, the sample pad buffer may comprisesalts of weak acids. In some embodiments, the sample pad buffer may beconcentrated to provide sufficient neutralization to the beverage, evenwith a miniaturized sample pad.

In one aspect, a method of detecting an analyte in a liquid describedherein comprises the steps of providing an apparatus comprising samplepad, a conjugate pad, and a detection layer, wherein the conjugate padcomprises at least one marker, such as an anti-analyte antibody-particleconjugate, and wherein the detection layer comprises ananalyte-conjugate protein and a chromatographic membrane capable ofreceiving the liquid and allowing for migration of the liquid; exposingat least the sample pad to the liquid; and determining whether aninteraction between the analyte-conjugate protein and the liquid occursto detect the presence of the analyte. In some embodiments, thedetection layer further comprises an anti-species antibody. In someembodiments, buffers or buffer solutions may be customized fordeposition into or onto the sample pad, conjugate pad, or detectionlayer. Thus, in some embodiments, the sample pad, conjugate pad, ordetection layer comprises residual buffer components. For example, abuffer solution may be deposited onto a detection layer and then driedto form test and/or control lines or areas. In some embodiments, thechromatographic membrane of the detection layer may comprise activatedcarbon, silica gel, ionic exchange resins, polyelectrolyte polymers,hydrogels, and/or size exclusion chromatography matrices. In someembodiments, the chromatographic membrane may comprise cellulose,nitrocellulose, glass fiber, similar materials or a combination of thesematerials. For the purposes of this application, “detection layer” and“detection area” may be used interchangeably.

In some embodiments, the marker comprises an anti-analyte antibodyconjugated to a particle. In other embodiments, the marker comprises ananti-analyte aptamer conjugated to a particle. For ease of discussionherein the term anti-analyte antibody-particle conjugate may be used torefer to either (or both) anti-analyte antibody-particle conjugates andanti-analyte aptamer-particle conjugates. The particle may be ananoparticle, microbead, macromolecule, small molecule, or othervisualization means. A visualization means may be any composition thatcontributes to a visible indication when the anti-analyteantibody-particle conjugate experiences an interaction, such as with ananalyte-conjugate protein or an anti-species antibody, to develop colorat a test or control line. In some examples, the particle is a coloredparticle, which may be a gold nanoparticle, a magnetic nanoparticle, ora dye-infused polymer microbead. In other embodiments, the particle maybe a fluorescent label conjugate, or a radiolabel. Optionally, theparticle includes carboxyfluorescein, 2,7-dichlorofluorescein, Eosin B,Eosin Y, erythrosine, fluorescein, fluorescein amidite, fluoresceinisocyanate, merbromin, phloxine B, Rose Bengal, derivatives or saltsthereof, or combinations thereof. The term anti-analyteantibody-particle conjugate and marker are used interchangeably herein.Unless otherwise specified, either term encompasses conjugates includingany suitable particles, such as those listed above. In some embodiments,the marker is present on the conjugate pad, which is generallypositioned between the sample pad and the chromatographic membrane.

In some embodiments, the conjugate pad may be pretreated with aconjugate pad buffer. In some embodiments, the conjugate pad buffer maybe quite concentrated because the conjugate pad may be very small, suchas 4 mm×4 mm. In some embodiments, the conjugate pad buffer mayneutralize compounds found in the liquid that might otherwise interferewith test results. In some examples, the conjugate pad buffer maycomprise organic polyols and/or amines, polyelectrolyte polymers,surfactants, and combinations thereof. Further, in some embodiments, theconjugate pad buffer is formulated to be compatible with theanti-analyte antibody-particle conjugate, or in other words, theconjugate pad buffer will not denature the anti-analyteantibody-particle conjugate.

In some embodiments, the anti-analyte antibody-particle conjugate isdissolved in a conjugate dilution buffer before being printed orotherwise deposited on the conjugate pad. For example, the conjugatedilution buffering agent can comprise organic salts, proteins, sugars,and combinations thereof.

In some embodiments, an analyte-conjugated protein deposited on thechromatographic membrane defines a test line or test area, and ananti-species antibody deposited defines a control line or control area.Both the test line and the control line may be immobilized on thechromatographic membrane. As explained further below, the “line” doesnot have to be linear, and may take various predetermined shapes thatinform the user of the presence or absence of the target substance. Insome embodiments, the test line or lines define a pattern, which maycomprise an indication such as “yes”, “no”, “safe”, “OK”, or “

”. In some embodiments, if the pattern has been created to detectmultiple analytes, only a certain portion of the pattern may changecolor. For example, the word “SAFE” may appear as SAFE, where the colorof the letter “A” has not developed in the cross-bar region. In someexamples, the pattern is formed with a stencil to create letters,symbols, or words. In some examples, the pattern is formed such that thetest results complete a design, word, symbol, or number.

In some examples, the liquid comprises a consumable liquid. For example,the consumable liquid can be beer, cider, an energy drink, a flavoreddrink, a fruit drink, liquor or another alcoholic beverage, milk or amilk-containing beverage, soda, a sports drink, a vegetable drink,water, wine, or a combination thereof. In some examples, the liquidcomprises a non-consumable liquid. For example, the non-consumableliquid can be blood, non-potable water, an organic solvent, potablewater, serum, treated waste water, untreated waste water, urine, vomit,or a combination thereof. The liquid can comprise a solution, asuspension, or an emulsion. In some embodiments, the liquid comprisessolid particles or ice suspended therein. In other embodiments, theliquid is used to extract an analyte from a solid material, such asextracting allergens from non-liquid food products, prior to detection.

In some embodiments, the detection layer is positioned on the surface ofan inert substrate. In some examples, the chromatographic membrane maybe pretreated with a chromatographic membrane buffering agent, whichmany interchangeably be called a detection layer buffering agent or adetection area buffering agent. The chromatographic membrane bufferingagent may comprise proteins, dibasic sodium phosphate, polyelectrolytepolymers, saccharides, or combinations thereof. In some examples, thechromatographic membrane may be buffered at a pH ranging from 7 to 8.

In another aspect, an apparatus described herein for detecting thepresence of an analyte in a liquid comprises a detection layer. In someembodiments, the apparatus comprises a sample pad capable of receivingthe liquid, a conjugate pad comprising an anti-analyte antibody-particleconjugate, and a detection layer comprising a chromatographic membraneallowing for migration of the liquid and comprising an analyte-conjugateprotein at a test location. In some embodiments, the chromatographicmembrane further comprises an anti-species antibody at a controllocation. In some embodiments, the detection layer further comprises anabsorbent, and/or is pre-treated with a desiccant. The absorbent caninclude chromatography paper, silica gel, or alumina. In some examples,the detection layer comprises a lateral flow assay, which may bemultiplexed for testing for the detection of multiple compounds.

In some examples, the sample pad is capable of receiving the liquid, andin some embodiments, the liquid moves from the sample pad to theconjugate pad to the chromatographic membrane. In some embodiments, theliquid moves from the chromatographic membrane to a wick. The wickserves a fluid reservoir to keep fluid from stalling on thechromatographic membrane. In some embodiments, in order to miniaturizethe assay, the wick is comprised of a folded layer (e.g., the layer isfolded back upon itself). In some embodiments, the wick is U-shaped orS-shaped. In some cases, the fluid path in the apparatus may be curvedthrough multiple planes and/or in multiple directions according to theshape of the components of the apparatus. As a result, in some examples,the overall length of the apparatus may be shortened without impedingthe detection ability of the apparatus. In some embodiments, theapparatus has a fluid path length greater than the length of theapparatus.

A particular advantage of miniaturization of a lateral flow assay istimeliness of test results. For example, a conventional lateral flowassay with an 80 mm long chromatographic membrane requires a minimum of5 minutes to display test results. In contrast, some embodiments of theminiaturized assays described herein display test results much faster.For example, a 12 mm detection layer comprising a residual bufferformulation as described herein requires only about 30 seconds todisplay test results. An additional advantage of a miniaturized lateralflow assay is reduced test fluid volume. In some examples, a samplevolume of no more than 15 μL is required for an apparatus describedherein, compared to 80 μL for a conventional 80 mm lateral flow assay.In some embodiments, sample volume is less than 40 μL, less than 30 μL,less than 20 μL, less than 10 μL, or less than 5 μL. In some embodimentstest results are displayed in less than 1 minute, less than 30 seconds,less than 15 seconds, less than 10 seconds, or less than 5 seconds.

In some embodiments, the apparatus further comprises a cover over thechromatographic membrane. The cover may comprise one or more openings topermit gas to escape, or the cover may be gas-permeable. In someembodiments, the cover is an opaque cover, a tinted cover, a transparentcover, or a translucent cover. In some embodiments, the cover defines astencil pattern, which may comprise an indication such as “yes”, “no”,“safe”, “OK”, or “

”. The stencil pattern may be placed over the second position of thechromatographic membrane. Such a pattern may be helpful to the user bymaking the test results easy to understand.

Optionally, the apparatus can be positioned on, within, or below anobject. In some embodiments, the object can be a fingernail, anartificial fingernail, a layer of fingernail polish, a fingernailsticker, a fingernail decal, a sticker, a cup, a drink coaster, a drinkstirrer, a toothpick, a drink ornament, a pencil, a pen, a ring, abracelet, a bracelet charm, a necklace, a lanyard pendant, a coaster, aswizzle stick, or another appropriate object. In some embodiments, theapparatus may be positioned on skin or on a fingernail.

In some embodiments, the miniaturized apparatus has a thickness of up to4 mm. In some embodiments, the length of the apparatus is up to 14 mm.In some examples, the width of the apparatus is up to 4 mm. In someembodiments, the miniaturized apparatus is configured to detect thepresence of multiple drugs in many varieties of beer, white wines, redwines, neat liquors, mixed drinks, soda, fruit juices, and water.

In some embodiments, an apparatus for detecting the presence of ananalyte in a liquid comprises a conjugate pad comprising a conjugatearea comprising at least one anti-analyte antibody-particle conjugate oranti-analyte aptamer-particle conjugate; a detection layer comprising achromatographic membrane and at least one analyte-conjugate protein, anda sample area for receiving a liquid, wherein the sample area is aseparate sample pad or is a portion of the conjugate pad separate fromthe conjugate area. In some examples, combining the sample pad andconjugate pad into a single membrane reduces the number of components inthe apparatus and improves manufacturability, in particular for aminiaturized lateral flow assay apparatus. In some examples, at leastone of the detection layer, the sample area, or the conjugate areacomprises a residual buffer composition. In other examples, theapparatus comprises a single pad comprising separate areas, such as asample area, a conjugate area, a detection layer (or chromatographicmembrane area), and a wick area. In still other examples, the apparatuscomprises a single pad comprising separate areas, such as a sample area,a conjugate area, and a detection layer (or chromatographic membranearea).

In some embodiments, the detection layer further comprises at least oneanti-species antibody. In some embodiments, the chromatographic membranecomprises one or more of cellulose, nitrocellulose, polyester fiber,and/or glass fiber. In some embodiments, the apparatus further comprisesa cover defining a pattern, wherein the cover is disposed over thedetection layer. In some embodiments, the detection layer is positionedon or within or under a natural fingernail, an artificial fingernail, alayer of fingernail polish, a fingernail sticker, a fingernail decal, asticker, a cup, a drink coaster, a drink stirrer, a toothpick, a drinkornament, a pencil, or a pen.

In some embodiments, the sample area comprises a first residual buffercomposition. The first residual buffer composition may comprise apotassium salt of a weak acid and at least one surfactant. In someembodiments, the conjugate area comprises a second residual buffercomposition. The second residual buffer composition may comprise aGood's buffer salt and one or more of a protein, an oligomer, a polymer,and a surfactant. In some embodiments, the detection layer comprises athird residual buffer composition. The third residual buffer compositionmay comprise a phosphate salt and one or more of a saccharide, aprotein, an oligomer, and a polymer.

In some embodiments, a method of detecting an analyte in a liquidcomprises providing an apparatus as described herein; exposing a portionof the apparatus to the liquid; and observing a visual indication todetermine presence or absence of the analyte.

In some embodiments, a method of making an apparatus for detecting thepresence of an analyte in a liquid comprises (1) applying a buffersolution to at least one of (a) a conjugate pad comprising a conjugatearea comprising at least one anti-analyte antibody-particle conjugate oranti-analyte aptamer-particle conjugate, (b) a detection layercomprising a chromatographic membrane and an analyte-conjugate protein,or (c) a sample area for receiving a liquid, wherein the sample area isa separate sample pad or is a portion of the conjugate pad separate fromthe conjugate area; (2) drying the buffer solution; and (3) assemblingthe conjugate pad, detection layer, sample area and a wick so that thesample area is in contact with one portion of the conjugate area,another portion of the conjugate area is in contact with a proximal endof the detection layer, and the wick is in contact with a distal end ofthe detection layer.

The details of one or more embodiments are set forth in the drawings anddescription below. Other features, objects, and advantages will beapparent from the drawings, the description, and from the claims.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is an exploded cross-sectional view of an apparatus according tosome embodiments described herein.

FIG. 2 is a cross-sectional view of an apparatus according to someembodiments described herein.

FIG. 3 shows test results of comparative assays and inventive assaysaccording to some embodiments described herein.

FIG. 4 shows test results of comparative assays and inventive assaysaccording to some embodiments described herein.

FIG. 5 shows test results of comparative assays and inventive assaysaccording to some embodiments described herein.

FIG. 6 shows test results of comparative assays and inventive assaysaccording to some embodiments described herein.

DETAILED DESCRIPTION

The subject matter of embodiments of the present invention is describedherein with specificity to meet statutory requirements, but thisdescription is not intended to limit the scope of the claims. Theclaimed subject matter may be embodied in other ways, may includedifferent elements or steps, and/or may be used in conjunction withother existing or future technologies. This description should not beinterpreted as implying any particular order or arrangement among orbetween various steps or elements except when the order of individualsteps or arrangement of elements is explicitly described. Theillustrative examples are given to introduce the reader to the generalsubject matter discussed herein and are not intended to limit the scopeof the disclosed concepts. The following sections describe variousadditional embodiments and examples with reference to the drawings inwhich like numerals indicate like elements and directional descriptionsare used to describe illustrative embodiments but, like the illustrativeembodiments, should not be used to limit the present invention.

Unless specifically stated to the contrary, the numerical parameters setforth in the following specification are approximations that can varydepending upon the desired properties sought to be obtained by thepresent invention. At the very least, and not as an attempt to limit theapplication of the doctrine of equivalents to the scope of the claims,each numerical parameter should at least be construed in light of thenumber of reported significant digits and by applying ordinary roundingtechniques.

Notwithstanding that the numerical ranges and parameters setting forththe broad scope of the invention are approximations, the numericalvalues set forth in the specific examples are reported as precisely aspossible. Any numerical value, however, inherently contains certainerrors necessarily resulting from the standard deviation found in itsrespective testing measurements. Moreover, all ranges disclosed hereinencompass any and all subranges subsumed therein. For example, a statedrange of “1 to 10” includes any and all subranges between (and inclusiveof) the minimum value of 1 and the maximum value of 10; that is, allsubranges beginning with a minimum value of 1 or more, e.g. 1 to 6.1,and ending with a maximum value of 10 or less, e.g., 5.5 to 10.

Described herein are apparatus and methods, and buffer solutions for usetherein, for detecting a targeted substance. In some embodiments, themethods and apparatus can detect a targeted compound in a liquid. Insome embodiments, the methods and apparatus can detect a targetedsubstance in a solid. As one example, the methods and apparatusdescribed herein can be used for real-time point-of-contact detection ofdrugs, such as date rape drugs or other sedating drugs, in beverages orbodily fluids. In other examples, the methods and apparatus describedherein can be used for real-time point-of-contact detection of heavymetals in foodstuffs or nutritional supplements, contaminants incosmetics, contaminants or nutrients in soils, or other analytes ofinterest. As another example, the methods and apparatus described hereincan be used for real-time detection of certain proteins or sugars, e.g.,gluten, peanut proteins, or lactose. In some embodiments, the methodsand apparatus described herein can be used for real-time detection ofother materials, for example, bacteria, pathogens, fungi, metals, orvolatile organics and other targeted compounds. In some examples,sedating drugs or date-rape drugs may be detected.

In some embodiments, benzodiazepine drugs may be detected.Benzodiazepines, or “benzos,” are a class of drugs having a chemicalstructure containing a benzene ring fused to a diazepine ring, as shownin formula (1) below. Benzodiazepines have sedating properties, and thusare used by criminals to incapacitate victims.

Benzodiazapines that may be detected include, but are not limited to,adinazolam, alprazolam, bentazepam, bretazenil, bromazepam, brotizolam,camezepam, chlordiazepoxide, cinazepam, cinolazepam, clobaxam,clonazepam, chorazepate, clotiazaepam, diazepam, flunitrazepam,lorazepam, lormetazepam, medazepam, midazolam, nitrazepam, oxaepam,temazepam, and thielnalprazolam.

In some embodiments, amine-containing compounds (e.g. amine-containingdrugs) may be detected. An “amine-containing” compound or drug, asreferred to herein, includes species having at least one primary,secondary, and/or tertiary amine, and/or salts thereof. The amineformula can be represented by NR¹R²R³, wherein R¹, R², and R³ can be thesame or different from one another, and R¹, R² and R³ can include, butare not limited to, hydrogen, substituted or unsubstitutedstraight-chained or branched C₁-C₆ alkyls (e.g., methyl, ethyl, propyl,butyl, pentyl, hexyl), substituted or unsubstituted C₆-C₁₀ aryls (e.g.,benzyl), substituted or unsubstituted straight-chained or branched C₁-C₆alkanols (e.g., methanol, ethanol, propanol, butanol, pentanol,hexanol), substituted or unsubstituted C₆-C₁₀ aryl, substituted orunsubstituted heteroaryl, substituted or unsubstituted C₄-C₈ cycloalkyl,or combinations thereof, with the proviso that R¹, R² and R³ cannot allbe hydrogen. The amine salts as described herein can be represented as(HNR¹R²R³)+X⁻, where X⁻ is a counterion and R¹, R² and R³ are as definedabove for amine. An amine-containing compound as described herein doesnot include ammonia or uronium compounds or salts thereof, such as ureaand derivatives and salts thereof, e.g., urea nitrate.

Examples of amine-containing compounds that may be detected include, forexample, amphetamine, cathinone, cyclobenzaprine, diphenhydramine,doxylamine, ephedrine, ketamine, lysergic acid diethylamide (LSD),methamphetamine, 3,4-methylenedioxyamphetamine (MDA),3,4-methylenedioxy-methamphetamine (MDMA), methcathinone,tetrahydrozoline and salts thereof, and combinations thereof.

In some embodiments, other drugs may be detected by the apparatus andmethods described herein. For example, steroids such as estrogens,gestogens, androgens, andrenocortical steroids, bile acids, cardiotonicglycosides and aglycones such as digoxin and digoxigenin, spaonins andsapogenins, their derivatives and metabolites may be detected.Barbiturates such as phenobarbital may be detected. Amphetamines;catecholamines such as ephedrine, L-dopa, epinephrine, carcene,papverin, and metabolites thereof may be detected. Alkaloids such asmorphine alkaloids may be detected. Purines such as theophylline,caffeine, and metabolites and derivative thereof may be detected.Marijuana derivatives such as cannabinol and tetrahydrocannabinol may bedetected. Vitamins such as A, B (such as B₁₂), C, D, E, K, folic acidand thiamine may be detected. Drugs that impair memory or sedating drugssuch as zolpidem, eszopiclone, ramelteon, zaleplon, doxepine, triazolam,temazepam, and alprazolam may be detected. Antibiotics such aspenicillin, chloromycetin, actinomycetin, tetracycline, terramycin, andmetabolites and derivative thereof may be detected. In addition,antihistamines, methadone, and other drugs may be detected.

The apparatus and methods described herein can detect a target substancein a liquid. The liquid may comprise a solution, a suspension, or anemulsion. In some examples, the liquid has solid particles or icesuspended therein.

In some embodiments, the liquid comprises a consumable liquid. Forexample, the consumable liquid can include beer, cider, energy drinks,flavored drinks, fruit drinks, liquor or other alcoholic beverages,milk, milk-containing beverages, soda, sports drinks, vegetable drinks,water, wine, or combinations thereof. In some embodiments, the liquidhas a high concentration of ethanol. In some embodiments, the liquid hasa high concentration of sugar. In some embodiments, the liquid isacidic.

In some examples, the liquid comprises a non-consumable liquid. Forexample, the non-consumable liquid can include blood, non-potable water,organic solvents, potable water, serum, treated waste water, untreatedwaste water, urine, vomit, sweat, tears, reproductive fluids, otherbodily secretions, or combinations thereof.

If the desired targeted substance is suspected to be in a non-liquid,for example, in a solid food, a suitable solvent may be used to extractat least some of the targeted substance, and that solvent may serve asthe liquid tested using apparatus and methods described herein.Similarly, nutritional supplements, cosmetics, or soil may be tested forpresence of heavy metals or undesirable chemicals by contacting thesolid with a solvent to extract any target analyte and testing thesolvent. Further, soluble air quality contaminants may be extracted fortesting. In some examples, the extraction employs a solvent or water.

The apparatus and methods described herein can provide preliminaryforensic analyses that can be of assistance to law enforcement orforensic experts, for example, by providing quick confirmation of thepresence or absence of a targeted analyte in the blood, sweat, tears,urine, vomit, or beverage of a person who may have ingested a targetcompound. Advantageously, the apparatus and methods described hereinallow for real-time determination of any of the above-mentionedanalytes. The methods described herein require no expensive equipment orscientific training to identify presence or absence of an analyte.

In some embodiments, an apparatus according to embodiments describedherein is a lateral flow device for a lateral flow assay, whereby aliquid being analyzed migrates along a fluid path from a sample area,across a conjugate area, and then across a chromatographic membrane to awick. The target substance or analyte, if present, reacts with ananti-analyte antibody, and the reaction results in a visual indicationof whether the target analyte is present in the liquid.

I. Buffer Solutions

Buffer solutions described herein may be applied to parts of a lateralflow apparatus as described herein to enhance performance of theapparatus. For example, a buffer solution may render a test apparatusand method as described herein compatible with liquids that containcomponents that otherwise would interfere with the analysis. Buffersolutions may also be used to slow liquid travel time across a membraneto ensure sufficient reaction time between any target analyte and acorresponding anti-analyte antibody or analyte-conjugate protein.

The buffer solutions described herein include salts, acids, proteins,excipients, viscosity modifiers, and/or surfactants. In thisapplication, “buffer,” “buffer solution,” and “buffer formulation” maybe used interchangeably to describe a solution comprising at least onebuffering compound and water. Optionally, the buffer solution mayfurther comprise buffer additives. Buffer additives are compounds thatdo not necessarily contribute to the buffering ability of the buffersolution (e.g., they do not substantially affect the acid-base chemistryof the buffer solution). In some embodiments, the buffering compoundsmay comprise buffer salts and optionally additional acids or bases, suchas hydrochloric acid or sodium hydroxide. In some embodiments, bufferadditives comprise shielding agents such as proteins, e.g. Bovine SerumAbumin (BSA); viscosity modifying polymers such as poly(vinyl alcohol)(PVA), poly(vinyl pyrrolidone) (PVP), poly(ethylene glycol) (PEG), oroligomers or copolymers thereof; excipients or stabilizing agents suchas saccharides (for example, dextran, trehalose, maltodextrose); andsurfactants such as non-ionic surfactants (for example, polysorbate 20or 80, Triton X-100, Triton X-305, or Pluronic F-68).

Buffer salts useful in the buffer solutions described herein includeweak acids and bases. The buffer salts may be mono-basic, di-basic,tri-basic, or have higher-order basicity, depending on how many protonsthe buffer salt can accept. For example, a mono-basic buffer salt willbe able to accept one proton, whereas a di-basic buffer salt can accepttwo protons. Similarly, acids useful in the buffer solutions describedherein can be mono-protic, di-protic, tri-protic, and so on, dependingon how many protons they can donate.

Traditional buffering acids and bases, such as boric acid, carbonicacid, and phosphoric acid, and their corresponding borate, carbonate,and phosphate salts may be used in the buffer solutions describedherein. In addition, Good's buffer salts, as described by Norman Goodand colleagues, and similar salts commonly used in biochemicalapplications may also be used. Non-limiting examples of buffer saltsuseful in the buffer solutions described herein are monosodiumphosphate, disodium phosphate, sodium tetraborate,tris(hydroxymethyl)methylaminopropanesulfonic (TAPS),N-cyclohexyl-2-aminoethanesulfonic acid (CHES),N-tris(hydroxymethyl)methyl-4-aminobutanesulfonic acid (TABS), bis-trismethane (Bis TRIS), tris(hydroxymethyl)aminomethane (TRIS),2-[[1,3-dihydroxy-2-(hydroxymethyl)propan-2-yl]amino]ethanesulfonic acid(TES), 2-(N-morpholino)ethanesulfonic acid (MES),N-(carbamoylmethyl)iminodiacetic acid (ADA),N-(2-acetamido)-2-aminoethanesulfonic acid (ACES), Bis tris propane,piperazine-N,N′-bis(2-ethanesulfonic acid)(PIPES),N-(2-acetamido)-2-aminoethanesulfonic acid (ACES),3-morpholino-2-hydroxypropanesulfonic acid (MOPSO), cholamine chloride,(3-(N-morpholino)propanesulfonic acid) (MOPS),N,N-bis(2-hydroxyethyl)taurine (BES),N,N-bis(2-hydroxyethyl)-3-amino-2-hydroxypropanesulfonic acid (DIPSO),4-(N-morpholino)butanesulfonic acid (MOBS),3-[N-tris(hydroxymethyl)methylamino]-2-hydroxypropanesulfonic acid(TAPSO), acetamidoglycine, triethanolamine (TEA),piperazine-N,N′-bis(2-hydroxypropanesulfonic acid) POPSO,4-(2-hydroxyethyl)piperazine-1-(2-hydroxypropanesulfonic acid) hydrate(HEPPSO), 3-[4-(2-hydroxyethyl)-1-piperazinyl]propanesulfonic acid(HEPPS), tricine, tris(hydroxymethyl)aminomethane, trometamol (TRIZMA),glycinamide, glycyl-glysine,N-(2-hydroxyethyl)piperazine-N′-(4-butanesulfonic acid) (HEPBS), bicine,2-amino-2-methyl-1-propanol (AMP),N-(1,1-dimethyl-2-hydroxyethyl)-3-amino-2-hydroxypropanesulfonic acid(AMPSO), N-cyclohexyl-2-hydroxyl-3-aminopropanesulfonic acid (CAPSO),N-cyclohexyl-3-aminopropanesulfonic acid (CAPS),4-(cyclohexylamino)-1-butanesulfonic acid (CABS), and(4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid) (HEPES). Otherpotentially useful buffer salts are salts of amino acids such as:alanine, arginine, asparagine, aspartic acid, cysteine, glutamic acid,glutamine, glycine, histidine, isoleucine, leucine, lysine, methionine,phenylalanine, proline, serine, threonine, tryptophan, tyrosine, valine.Further, buffer salts could include carnitine, gamma-aminobutyric acid,taurine.

The following examples disclose buffering compounds according to someembodiments. In some examples, a buffer solution comprises TRIS(tris(hydroxymethyl)aminomethane) and water. The concentration of TRISin the buffer solution can be up to 0.3 M, up to 0.4 M, up to 0.5 M, upto 0.60 M, up to 0.7 M, up to 0.8 M, or up to 1.0 M. In some embodimentsthe TRIS concentration is about 0.5 M.

In some embodiments, a buffer solution useful in the methods andapparatus described herein comprises a dibasic salt, a monobasic salt,and water. In some embodiments, the dibasic salt and monobasic salt havea common anion. For example, the common anion may be a phosphate anion,although any other known dibasic anion may be used. The cation may beany monovalent or divalent cation, such as potassium, sodium, orcalcium. In some examples, the buffer solution comprises sodiumphosphate monobasic and/or sodium phosphate dibasic.

In other embodiments, a buffer solution useful in the methods andapparatus described herein comprises one or more phosphate salts, one ormore chloride salts, or a combination thereof, and water. Examples ofuseful chloride salts include sodium chloride and/or potassium chloride.Optionally, the one or more phosphate salts include disodium phosphateand/or potassium dihydrogen phosphate. Optionally, the salts used toprepare the phosphate buffer solution are hydrates. The hydrate may be,for example, a monohydrate, a dihydrate, a trihydrate, a tetrahydrate, apentahydrate, a hexahydrate, or a heptahydrate. In some embodiments, thedisodium phosphate used to prepare the phosphate buffer may be disodiumphosphate heptahydrate (Na₂HPO₄.7H₂O). A phosphate salt may be presentin the buffer in an amount of up to 25 mM, up to 25 mM, up to 50 mM, upto 100 mM, up to about 200 mM, from about 5 to about 15 mL, from about20 to about 25 mM, from about 40 to about 60 mM, or from about 80 toabout 120 mM.

In some embodiments a buffer solution useful in the methods andapparatus described herein comprises a borate salt and water.Optionally, the borate salt is a hydrate. As described above, thehydrate may be, for example, a monohydrate, a dihydrate, a trihydrate, atetrahydrate, a pentahydrate, a hexahydrate, or a heptahydrate. Forexample, the borate salt used to prepare the borate buffers can betetraborate heptahydrate (Na₂B₄O₇.10H₂O). Borate salts may be present inthe buffer in amounts of up to 25 millimolar, up to 50 mM, or up to 100mM.

In some embodiments, a buffer solution useful in the methods andapparatus described herein comprises one or more carboxylates such assuccinate and citrate and water. In some embodiments, a buffer solutioncomprises a monovalent cation carbonate, such as potassium carbonate(K₂CO₃) or divalent cation carbonate, such as calcium carbonate (CaCO₃).For example, potassium carbonate may be present in the buffer solutionin amounts of up to 500 mM, up to 750 mM, up to 1.0 M, up to 1.1 M, upto 1.2 M, up to 1.3 M, up to 1.4 M, or up to 1.5 M.

In some embodiments, a buffer solution useful in the apparatus andmethods described herein includes acids or bases in addition to any weakacid or base buffering compounds. These additional acids and bases maybe used to adjust the final pH of the buffered solutions. In someembodiments, hydrochloric acid (HCl) or sodium hydroxide (NaOH) may beused as such additional acid or base, although other acids or basescould be used instead.

The following examples disclose buffer additives according to someembodiments. In some embodiments, a buffer solution useful in themethods and apparatus described herein may include one or more shieldingagents. In some embodiments a shielding agent is a protein. Non-limitingexamples of shielding agents include gelatin, casein, and Bovine SerumAlbumin (BSA). In some examples, a buffer solution may comprise BSA inany amount from less than 1 percent to more than 10 percent based on theweight of the buffer solution. In some embodiments, the buffer solutioncomprises BSA in about 0.1%, about 0.2 wt %, about 0.5 wt %, about 1 wt%, about 3 wt %, about 5 wt %, about 8 wt %, about 10 wt %, about 12 wt%, or about 15 wt % based on the weight of the buffer solution.

In some embodiments, a buffer solution useful in the apparatus andmethods provided herein may include at least one excipient (e.g., one,two, three, four, or more excipients). Useful excipients include, butare not limited to, saccharides and amino acids. Useful saccharidesinclude, for example, monosaccharides and disaccharides, such as but notlimited to sucrose, mannitol, sorbitol, lactose, dextrose, fructose,glucose, maltose and combinations thereof. In some examples, the buffersare substantially free of saccharides other than sucrose (for example,the buffers are substantially free of non-sucrose polyols).Substantially free of non-sucrose polyols means including less than0.1%, less than 0.01%, less than 0.001%, less than 0.0001%, or 0% ofnon-sucrose polyols based on the weight of the buffer.

In some embodiments, buffer solutions useful in the apparatus andmethods provided herein comprise viscosity modifiers. Suitable viscositymodifiers include, but are not limited to, saccarides, such as sucrose,and polymers, such as poly(vinyl alcohol) (PVA), poly(vinyl pyrrolidone)(PVP), poly(ethylene glycol) (PEG), or oligomers or copolymers thereof.Any molecular weight polymer or oligomer may be used, provided thepolymer or oligomer is soluble in the buffer solution. In someembodiments, poly(vinylpyrrolidone)-40 (PVP-40) is used to increase theviscosity of the buffer solution. In some embodiments, the viscositymodifier is present at up to 0.1 wt %, up to 0.2 wt %, up to 0.3 wt %,up to 0.4 wt %, up to 0.5 wt %, up to 0.6 wt %, up to 0.7 wt %, up to0.8 wt %, up to 0.9 wt %, up to 1.0 wt %, up to 2.0 wt %, up to 3.0 wt%, up to 4.0 wt %, or up to 5.0 wt % based on the total weight of thebuffer solution.

In some embodiments, buffer solutions useful in the apparatus andmethods provided herein comprise at least one detergent or surfactant.Detergent and surfactant refer to a substance having both a hydrophilicmoiety and a hydrophobic moiety. Useful surfactants include ionic andnon-ionic surfactants. In some examples, Triton X-35, Triton X-100,and/or Pluronic F-68 is optionally included as the non-ionic surfactantin a buffer solution. One or more surfactants can be present in thebuffers, optionally in an amount of less than 1% by weight based on theweight of the buffer. For example, the surfactant(s) can be present inthe buffers in an amount of up to 3%, up to 2%, up to 1%, up to 0.75%,up to 0.5% by weight, up to 0.25% by weight, up to 0.1% by weight, or upto 0.05% by weight (e.g., 0.25% by weight or 0.5% by weight).

In some embodiments, the surfactant may be one or more non-ionicsurfactant such as fatty alcohols, polyethylene glycol alkyl ethers,polypropylene glycol alkyl ethers, glucoside alkyl ethers, polyethyleneglycol octyl, glycerol alkyl esters, phenyl ethers (such as TritonX-100), polyoxyethylene (20) oleyl ether (such as Brig 98), octylphenolethoxylate (such as Triton X-305), polyethylene glycol alkylphenylethers, polyethoxylated tallow amine,N,N-bis[3-(D-gluconamido)propyl]cholamide, polyoxyethylene (20) cetylether, dimethyldecylphosphine oxide, branched octylphenoxypoly(ethyleneoxy)ethanol, a polyoxyethylene-polyoxypropylene blockcopolymer, t-octylphenoxypolyethoxyethanol, polyoxyethylene (20)sorbitan monooleate, alkyl polyglycosides, polysorbates (such andTween), or poloxamers (such Synperonics, Pluronics, or Kolliphor).

In some embodiments, the surfactant may be an anionic surfactant such as2-acrylamido-2-methylpropane sulfonic acid, ammonium lauryl sulfate,ammonium perfluorononanoate, docusate, perfluorobutanesulfonic acid,perfluorononanoic acid, perfluorooctanesulfonic acid, perfluorooctanoicacid, sodium alkyl sulfate, sodium dodecyl sulfate, sodiumdodecylbenzenesulfonate, sodium laurate, sodium laureth sulfate, sodiumlauroyl sarcosinate, sodium myreth sulfate, sodiumnonanoyloxybenzenesulfonate, sodium pareth sulfate, or sodium stearate.

In some embodiments, the surfactant may be a cationic surfactant such asbehentrimonium chloride, benzalkonium chloride, benzethonium chloride,cetrimonium bromide, cetrimonium chloride, dimethyldioctadecylammoniumbromide, dimethyldioctadecylammonium chloride, lauryl methyl gluceth-10hydroxypropyl dimonium chloride, octenidine dihydrochloride,N-oleyl-1,3-propanediamine, stearalkonium chloride, ortetramethylammonium hydroxide.

In some embodiments, the surfactant may be a zwitterionic surfactantsuch as CHAPS detergent, cocamidopropyl betaine, cocamidopropylhydroxylsultaine, lauryldimethylamine oxide, and Sodiumlauroamphoacetate. These surfactant examples are non-limiting, as othernonionic, anionic, cationic, or zwitterionic surfactants may be used.

Buffer solutions provided herein may be used to pretreat one or morespecific areas of an apparatus to deposit buffering compounds and bufferadditives in one or more desired locations of the apparatus. In someembodiments, a buffer solution is applied to the respective portion ofthe apparatus as a solution or suspension, then the liquid portion ofthe buffer solution is removed (e.g. by evaporation) leaving a residualbuffer component comprising one or more residual buffering compoundsand, any residual buffer additives present in the buffer solution. Theresidual buffer component includes any buffer components that remainafter the liquid medium (e.g. water) is removed. As a test liquidtraverses the apparatus, it comes into contact with the deposited buffercomponents and any residual buffer additive and dissolves them,essentially reconstituting the buffer solution. The term “reconstituted”does not imply that the buffer solution formed in the test liquid hasthe same concentration as the buffer solution used to pre-treat theapparatus or that the solutions are identical. The reconstituted buffersolution may have a different concentration than the buffer solutionused to pre-treat the apparatus.

For example, a first buffer solution may be applied to a sample area todeposit buffering compounds and buffer additives selected to neutralizeor counteract beverage components that might interfere with a testresult. Another buffer solution may be applied to the chromatographicmembrane to increase the viscosity of the beverage or liquid, forexample to slow its migration across the chromatographic membrane. Insome embodiments specific combinations of buffer solutions may be usedin an apparatus where a first buffer solution is applied to the samplearea, a second buffer solution is applied to the chromatographicmembrane, and the first and second buffer solutions are different. Suchcombinations of buffer solutions can be used synergistically to improvethe performance of the apparatus and methods across a wide range of testliquids.

In some embodiments, specific combinations of neutralizing agents,buffering agents, and surfactants are used synergistically to improvethe performance of the assay across a wide range of sample matrices.Neutralizing agents can be used alone or in combination with bufferingagents to improve assay performance across a diverse set of testliquids. Neutralizing reagents may include traditional buffering agents,such as Good's buffer salts, and other acidic or basic components whichtreat the sample prior to the sample encountering the detection means.Neutralizing reagents may consist of carboxylate salts such as sodiumcitrate or potassium carbonate. Buffering reagents create a stable andconsistent environment for the detection means to function within andmay consist of ionic or zwitterionic buffer salts. Buffering agentsalone may not provide adequate neutralization of all sample types.Neutralizing agents alone may be too acidic or basic to be compatiblewith the detection means. For example, one potential combination ofneutralizing agent and buffering agent is potassium carbonate (0.1 to3M) and tris (0.1M to 3M), respectively, at any combination ofneutralizing and buffering agent concentrations within the specifiedranges. In some embodiments, the ratio of neutralizing agent tobuffering agent is 2:1.

The neutralizing agent may be located in an assay component such as thesample pad or area which is separate from the buffering agent located inthe conjugate pad or area. In some cases, the neutralizing agent isK₂CO₃ (0.1 to 3M) or other carboxylate salt. In some cases, thebuffering agent is Tris (0.1M to 3M) or other Good's buffer agent.Separation of the neutralizing agent from the conjugate pad is ofparticular importance when the neutralizing agent is not compatible withthe antibody-particle conjugate as is the case with K₂CO₃ andantibody-gold nanoparticle conjugates. The neutralizing agent maydeposited on the same assay component but in a separate area from thedetection means. In some cases, the neutralizing agent is K₂CO₃ (0.1 to3M) or other carboxylate salt. In some cases, the buffering agent isTris (0.1M to 3M) or other Good's buffer agent.

In some embodiments, certain combinations of non-ionic surfactants areparticularly useful for ensuring an apparatus described herein iscompatible with a wide range of test liquids. These non-ionicsurfactants may be used alone or in conjugation with neutralizing andbuffering agents. In some examples, a first non-ionic surfactant isPluronic F68 (0.1% to 2%) or other poloxamer and a second non-ionicsurfactant is Triton X-100 (0.1% to 2%) or other polyethylene oxidephenyl ether at any combination of concentrations within the statedranges for each compound. Buffer formulations and residual bufferformulation may comprise a first and a second non-ionic surfactant atany combination of concentrations within the stated ranges for eachsurfactant. The non-ionic surfactants may be located in the conjugatepad. The non-ionic surfactants may be located in the sample pad. Onenon-ionic surfactant may be located in the sample pad and one non-ionicsurfactant may be located in the conjugate pad.

In some embodiments, combinations of neutralizing agents, bufferingagents, and non-ionic surfactants were found to improve assayperformance. For example, a useful combination includes the neutralizingagent K2CO3 (0.1 to 3M), buffering agent Tris (0.1M to 3M), thenon-ionic surfactant Triton X-100 (0.1 to 2%), and a second non-ionicsurfactant Pluronic F68.

In some embodiments a buffer solution described herein comprises adibasic salt and water. In some embodiments, the buffer solutioncomprises sodium phosphate monobasic and sodium phosphate dibasic. Inone specific example, a buffer solution comprises sodium phosphatemonobasic in an amount of 5-20 grams per liter and sodium phosphatedibasic in an amount of 540-80 grams per liter. In some embodiments, thewater is molecular biology reagent grade water. The buffer solution isprepared by placing 0.7-0.9 liter of water in a container, adding theprescribed amounts of monobasic and dibasic salts, and then adding waterto one liter. The pH of the buffer solution is adjusted to the desiredpH using NaOH or HCl as needed, and the buffer solution is filteredusing a micron filter.

In some embodiments, the monobasic salt may be present in 11.4, 11.2,11.0, 10.8, 10.6, 10.4, 10.2, 10.0, 9.8, 9.6, 9.4, or 9.2 grams timesthe batch volume. In some embodiments, the dibasic salt may be presentin 70, 65, 60, 55, 50, or 45 grams times the batch volume. If saltsother than sodium phosphate monobasic and sodium phosphate dibasic areused, these amounts may be adjusted as understood by one of skill in theart. In some embodiments, the buffer solution has a pH of 7.3, 7.4, 7.5,7.6, 7.7, or 7.8, or any number in this range. A sodium phosphatemonobasic/sodium phosphate dibasic buffer solution is useful forapplying reagents to an apparatus. Specifically, in some embodiments, asodium phosphate monobasic/sodium phosphate dibasic buffer solution maybe used as an elution buffer to desalt an antibody that has been stored.

A buffer solution described herein may comprise a borate salt, boricacid, and water. In some embodiments, the buffer solution may comprise aborate salt, boric acid, BSA, water, and optionally sodium hydroxide orhydrochloric acid. In some examples, the buffer solution comprisessodium tetraborate decahydrate in an amount of 5-20 grams per liter ofbuffer solution and boric acid in an amount of 0.5-2 grams per liter ofbuffer solution. In some embodiments, BSA is present in an amount of5-20 grams per liter of buffer solution. In some embodiments, the wateris molecular biology reagent grade water. In some embodiments, thebuffer solution is prepared by measuring the dry reagents into acontainer, and adding water to final volume. In some embodiments, the pHof the buffer solution is adjusted to the desired pH using NaOH or HClas needed. In some examples the buffer solution is filtered using a 0.2micron filter.

In some embodiments, the sodium tetraborate decahydrate may be presentin 16, 14, 12, 11.8, 11.6, 11.4, 11.2, 11.0, 10, 9, or 8 grams per literof buffer solution, or any number within this range. In embodiments, theboric acid may be present in 2.0, 1.8, 1.6, 1.4, 1.2, 1.0, 0.8, 0.6, or0.4 grams per liter of buffer solution, or any number within this range.In some examples, BSA may be present at 12, 11, 10, 9, or 8 grams perliter of buffer solution. In some embodiments, the buffer solution has apH of 9.5, 9.4, 9.3, 9.2, 9.1, 9.0, 8.9, 8.8, 8.7, 8.6, or 8.5, or anynumber within this range. This borate buffer solution is useful forapplying reagents to an apparatus. Specifically, in some embodiments,this borate buffer solution may be used as a conjugation blocking bufferin the preparation of an antibody-particle conjugate.

A buffer solution described herein may comprise a borate salt, boricacid, and water. In some embodiments, the buffer solution may compriseborate salt, boric acid, BSA, water, and optionally sodium hydroxide orhydrochloric acid. In some examples, the buffer solution comprisessodium tetraborate decahydrate in an amount of 5-20 grams per liter ofbuffer solution and boric acid in an amount of 0.5-20 grams per liter ofbuffer solution. In some embodiments, BSA is added in an amount of50-200 grams per liter of buffer solution. In some embodiments, thewater is molecular biology reagent grade water. In some embodiments, thebuffer solution is prepared by measuring the dry reagents into acontainer, and adding water to final volume. In some embodiments, the pHof the buffer solution is adjusted to the desired pH using NaOH or HClas needed. In some examples the buffer solution is filtered using a 0.2micron filter.

Other borate buffers comprising different concentrations of BSA may alsobe useful. In other embodiments, the sodium tetraborate decahydrate maybe present in 16, 14, 12, 11.8, 11.6, 11.4, 11.2, 11.0, 10, 9, or 8grams per liter of buffer solution. In some other embodiments, the boricacid may be present in 2.0, 1.8, 1.6, 1.4, 1.2, 1.0, 0.8, 0.6, or 0.4grams per liter of buffer solution, or any number within this range. Insome other examples, BSA may be present at 120, 110, 100, 90, or 80grams per liter of buffer solution. In some other embodiments, thebuffer solution has a pH of 9.5, 9.4, 9.3, 9.2, 9.1, 9.0, 8.9, 8.8, 8.7,8.6, or 8.5, or any number within this range. This other borate buffersolution is useful for applying reagents to an apparatus. Specifically,in some embodiments, this buffer solution may be used as a conjugatedilution buffer in applying an antibody-particle conjugate to anapparatus.

A buffer solution described herein may comprise a dibasic salt andwater. In some embodiments, a useful buffer solution comprises sodiumphosphate monobasic and sodium phosphate dibasic; one or more of asaccharide, a protein, and a viscosity modifier; one or more of sucrose,BSA, and poly(vinylpyrrolidone)-40 (PVP-40); and optionally sodiumhydroxide or hydrochloric acid. In some examples, the buffer solutioncomprises sodium phosphate monobasic in an amount of 0.1-0.5 grams perliter of buffer solution and sodium phosphate dibasic in an amount of0.5-3 grams per liter of buffer solution. In some examples, the buffersolution further comprises 0.5-2 g sucrose per liter of buffer solution,0.5-2 g BSA per liter of buffer solution, and 1-5 g PVP-40 per liter ofbuffer solution. In some embodiments, the water is molecular biologyreagent grade water. In some embodiments, the buffer solution isprepared by adding the prescribed amounts of monobasic and dibasicsalts, adding the sucrose, BSA, and PVP-40, and then adding water tofinal volume. In some embodiments, the pH of the buffer solution isadjusted to the desired pH using NaOH or HCl as needed. In some examplesthe buffer solution is filtered using a 0.2 micron filter.

In some embodiments, the monobasic salt may be present in 0.3, 0.2, or0.1 grams per liter of buffer solution. In some embodiments, the dibasicsalt may be present in 2, 1.8, 1.6, 1.4, 1.2, 0.8, 0.6, or 0.5 grams perliter of buffer solution. If salts other than sodium phosphate monobasicand sodium phosphate dibasic are used, these amounts may be adjusted asunderstood by one of skill in the art. Sucrose may be present in 2, 1,or 0.5 grams per liter of buffer solution. BSA may be present in 2, 1,or 0.5 grams per liter of buffer solution. PVP-40 may be present in 4,2, or 1 grams per liter of buffer solution. In some embodiments, thebuffer solution has a pH of 7.3, 7.4, 7.5, 7.6, 7.7, or 7.8, or anynumber in this range. This buffer solution is useful for slowing theflow of a liquid in an apparatus. Specifically, in some embodiments,this buffer solution may be used as a pretreatment buffer solution for achromatographic membrane in an apparatus.

A buffer solution described herein may comprise a Good's buffer salt andwater. In some embodiments a buffer solution comprises a Good's buffersalt, a protein, a viscosity modifier, optionally one or moresurfactants, and optionally one or more additional acids or bases. Insome examples, the buffer solution comprises TRIS. In some embodiments,the buffer solution comprises TRIS, BSA, PVP-40, optionally one or moreof Triton X-100 and Pluronic F-68, optionally sodium hydroxide orhydrochloric acid. In some examples, the buffer solution comprises TRISin an amount of 50-200 grams per liter of buffer solution. In someexamples, the buffer solution further comprises 20-40 g BSA per liter ofbuffer solution, and 5-20 g PVP-40 per liter of buffer solution. In someembodiments, the buffer solution further comprises 1-5 g Triton X-100per liter of buffer solution and 2-10 g Pluronic F-68 per liter ofbuffer solution. In some embodiments, the water is molecular biologyreagent grade water. In some embodiments, the buffer solution isprepared by adding the prescribed amounts of TRIS, adding the BSA, andPVP-40, Triton X-100 and Pluronic F-68, and then adding water to finalvolume. In some embodiments, the pH of the buffer solution is adjustedto the desired pH using NaOH or HCl as needed. In some examples thebuffer solution is filtered using a 0.2 micron filter.

In some embodiments, the TRIS may be present in about 150, 140, 130,120, 115, 110, 100, 90, or 80 grams per liter of buffer solution. BSAmay be present in 40, 35, 32, 30, 28 or 25 grams per liter of buffersolution. PVP-40 may be present in about 20, 15, 12, 10, 8 or 55 gramsper liter of buffer solution. Triton X-100 may be present in about 5, 4,3, 2.8, 2.5, 2.3, or 2 grams per liter of buffer solution. Pluronic F-68may be present in about 8, 7, 6, 5.5, 5, 4.5, 4, 3.5, 3, or 2 grams perliter of buffer solution. In some embodiments, the buffer solution has apH of 7.6, 7.8, 8.0, 8.2, or 8.4, or any number in this range. Thisbuffer solution is useful for pretreating a component of an apparatus.Specifically, in some embodiments, this buffer solution may be used as apretreatment buffer solution for a conjugate pad in an apparatus.

A buffer solution described herein may comprise a carboxylate and water.In some examples, the buffer solution comprises potassium carbonate.Optionally, the buffer solution may comprise one or more surfactants. Insome embodiments, the buffer solution comprises a carboxylate (such aspotassium carbonate), water, optionally one or more surfactants, andoptionally one or more additional acids or bases. In some embodiments,the surfactant is Triton X-305. In some examples, the buffer solutioncomprises potassium carbonate in an amount of 50-200 grams per liter ofbuffer solution. In some examples, the buffer solution further comprises1-10 g Triton X-305 per liter of buffer solution. In some embodiments,the water is molecular biology reagent grade water. In some embodiments,the buffer solution is prepared by adding the prescribed amounts ofpotassium carbonate and Triton X-305 to a container, and then addingwater to final volume. In some embodiments, the pH of the buffersolution is adjusted to the desired pH using NaOH or HCl as needed. Insome examples the buffer solution is filtered using a 0.2 micron filter.

In some embodiments, the potassium carbonate may be present in about150, 140, 138, 136, 130, 120, 110, 100, or 80 grams per liter of buffersolution. Triton X-100 may be present in about 5, 4, 3.8, 3.6, 3.4, 3,2.5, or 2 grams per liter of buffer solution. In some embodiments, thebuffer solution has a pH of 7.4, 7.2, 7.0, 6.8, or 4.4, or any number inthis range. This buffer solution is useful for pretreating a componentof an apparatus. Specifically, in some embodiments, this buffer solutionmay be used as a pretreatment buffer solution for a sample pad in anapparatus.

II. Methods of Detecting Targeted Compounds

Methods of detecting targeted compounds, including substances of abuseand/or drugs, are described herein.

Examples of non-limiting methods of detecting an analyte according toembodiments described herein include providing an apparatus comprising asample pad, a conjugate pad, a detection layer comprising achromatographic membrane, and a wick. The apparatus is described ingreater detail in Section III. The chromatographic membrane of theinvention is capable of receiving the liquid being tested and alsoallows for migration of the liquid through the chromatographic membrane,in some embodiments by capillary action. The sample pad is exposed tothe liquid, for example by direct contact with the liquid, the liquidmigrates from the sample pad to the conjugate pad (or from the samplearea to the conjugate area), and then the liquid advances through theconjugate pad (or area), and then through the chromatographic membrane.As the liquid advances through the apparatus, the conjugate pad (wherethe anti-analyte antibody-particle conjugate is located) is exposed tothe liquid, and the anti-analyte antibody-particle conjugate becomes atleast partially dissolved in the liquid.

In some embodiments, aptamers may be used instead of or in addition toantibodies. For ease of discussion the term antibodies is usedthroughout this application, but throughout the specification should beunderstood to encompass both antibodies and aptamers.

The method further includes determining whether an interaction betweenthe anti-drug antibody-particle conjugate and the liquid occurs todetect the presence of the analyte. The determining step comprisesmonitoring the test line (where the analyte-conjugate protein islocated) to observe whether the test line develops color, and optionallywhether a control line develops color, as described below. Thus, thedetermining step comprises observing a visual indication to determinepresence or absence of the analyte.

If the liquid contains an analyte that matches the anti-analyte antibodyof the anti-analyte antibody-particle conjugate, the analyte will bindto the anti-analyte antibody portion of the conjugate, and because theanti-analyte portion of the conjugate is bound to the analyte, theanti-analyte antibody portion cannot not bind to the analyte-conjugateprotein, and no color will be deposited at the test line. However, ifthe liquid is substantially free from an analyte that matches theanti-analyte antibody of the anti-analyte antibody-particle conjugate,the anti-analyte antibody-particle conjugate will bind to theanalyte-conjugate protein and color will be deposited at the test line.

Optionally, the chromatographic membrane may comprise an anti-speciesantibody at a control line. Regardless of whether an analyte is bound tothe anti-analyte antibody-particle conjugate, the control line willdevelop color when the anti-analyte antibody-particle conjugate is drawnby the liquid to the control line.

Using a competitive (indirect) immunoassay format, a result indicatingthat no analyte is present consists of two lines (test and control linesare visible) while a result indicating that analyte is present consistsof one line (control line is visible) in some examples. In otherexamples where a control line is not employed, a result indicating thatno analyte is present consists of one line (test line is visible) whilea result indicating that analyte is present consists of no line. Areasof color deposition are not limited to lines, and may comprise symbolsor patterns. The phrases “test line, test location, test pattern, testsymbol, and test area” may be used interchangeably. The phrases “controlline, control location, control pattern, control symbol, and controlarea” may be used interchangeably. Alternately, a direct immunoassayformat may be used, where the visible presence of a test line indicatesthe target analyte is present.

In some embodiments, the method comprises observing a visual indicationor signal mechanism as to whether a particular compound is present. Forexample, the indication can comprise the appearance of a colored dot,pattern, or region, the absence of any appearance of a colored region,the printing of words, such as “SAFE,” “OK,” “YES,” or “NO,” checkmarks,emoticons or symbols such as a “

,” fluorescence, vibration, or sounds. In some examples, the signalingmechanism comprises completing lines, logos, patterns or symbols. Insome embodiments, if the pattern has been created to detect multipleanalytes, only a certain portion of the pattern may change color. Forexample, the word “SAFE” may appear as SAFE, where the color of theletter “A” has not developed in the cross-bar region.

The method described herein does not rely on the observation ormeasurement of color change of the anti-analyte antibody-particleconjugate to detect the presence of an analyte in a liquid. The methoddescribed herein does not rely on other techniques, such aselectrophoresis. The method relies on observing color deposition (orlack thereof) at the test and/or control lines, area, or patterns, orregions.

Any of the apparatus described in the section below may be used in themethods described herein.

III. Apparatus

Certain embodiments described herein provide an apparatus for detectingthe presence of a targeted substance, analyte, or drug in a liquid,wherein the apparatus comprises a sample pad, a conjugate pad, and adetection layer, and in some cases, a wick. In some embodiments, thedetection layer can detect the presence of a particular substance uponreceiving a liquid to be tested for the particular targeted substance.For example, the sample pad can be exposed to the liquid in question andthen the apparatus may be monitored by a user to determine whether thereis a particular interaction between the detection layer and the liquidto indicate the presence of the targeted substance. In some embodiments,the particular substance is a benzodiazepine or an amine-containingcompound. In other embodiments, the particular substance is a protein orsugar.

In other examples, the apparatus comprises a single pad comprisingseparate areas, such as a sample area, a conjugate area, a detectionlayer (or chromatographic membrane area), and a wick area. In stillother examples, the apparatus comprises a single pad comprising separateareas, such as a sample area, a conjugate area, and a detection layer(or chromatographic membrane area).

In some embodiments, the apparatus can be configured to minimize,substantially reduce, or eliminate backflow. This backflow or potentialflow of components from the apparatus to the test liquid may beundesirable, especially for testing of consumable liquids. In someembodiments, the potential backflow/reverse flow may comprise the testliquid and chemicals from the apparatus. To address the potential forbackflow, in some embodiments, the detection layer may further comprisean untreated pad at the sample port or opening in the top layer tosubstantially eliminate backflow. The untreated pad may minimize,substantially reduce, or eliminate potential flow of material back tothe test liquid due to saturation of the untreated pad upon introductionof the apparatus into the test liquid. Once introduced into the testliquid, the saturated untreated pad may serve as a constraint onbackflow by minimizing the gradient and motive force of flow from thesample pad to the test liquid. This constraint of the saturateduntreated pad may help ensure that essentially none of the chemicaladditives or buffers from the apparatus come in contact with the testliquid. In some examples, preventing backflow can be achieved by usingan untreated sample pad and/or by designing the apparatus to encase thecomponents of apparatus (other than the untreated pad and/or sample pad)in a plastic housing.

In some embodiments, the apparatus is a lateral flow device for alateral flow assay, whereby a liquid to be analyzed migrates along afluid path from a sample area, across a conjugate area, across achromatographic membrane, and into a wick. The target substance oranalyte, if present, reacts with an anti-analyte antibody and thereaction results in a visual indication of whether the target analyte ispresent in the liquid. In some examples, aptamers may be used instead ofor in addition to antibodies. Lateral flow assays typically have a fluidpath along the length of the apparatus. In some examples disclosedherein the length of the fluid path is the same as the length of theapparatus. In other examples, the length of the fluid path is greaterthan the length of the apparatus, Although the term “lateral flow” isused throughout this specification, in some cases the fluid path mayvary in the x-y plane or in the z direction in order to achievedetection results in an apparatus with a confined length. In suchembodiments, the length of the fluid path typically is greater than thelength of the apparatus.

An apparatus for detecting the presence of a targeted substance in aliquid comprises a sample pad; a conjugate pad that includes abinder-particle conjugate, such as an anti-analyte antibody-particleconjugate; and a chromatographic membrane, optionally including ananalyte-conjugate protein. In some embodiments, the sample pad and theconjugate pad are formed from a single material comprising a sample areaand a conjugate area; the sample area and the conjugate area do notoverlap. In some embodiments, the anti-analyte antibody-particleconjugate can be included in the conjugate pad by depositing acomposition comprising an anti-analyte antibody-particle conjugate onthe chromatographic membrane from a conjugate dilution buffer. Theanalyte-conjugate protein can be included in the chromatographicmembrane at a test location by depositing a composition comprising ananalyte-conjugate protein on the chromatographic membrane in a line ordesired pattern. Optionally, an anti-species antibody can be included inthe chromatographic membrane at a control location by contacting thechromatographic membrane with a composition comprising an anti-speciesantibody.

The wick serves a fluid reservoir to keep fluid moving through thechromatographic membrane. In some embodiments, in order to miniaturizethe assay, the wick is comprised of a folded layer (e.g., the layer isfolded back upon itself). In some embodiments, the wick is U-shaped orS-shaped. In some cases, the fluid path in the wick may be curvedthrough multiple planes and/or in multiple directions according to theshape of the wick. As the fluid flows from the chromatographic membraneto the wick, it continues along a fluid path within the wick. In someexamples, the fluid path through the wick is not aligned with the pathof the fluid through the chromatographic membrane, as the wick maydirect the fluid path to the sides of and/or around or under thechromatographic membrane.

In some embodiments, the apparatus can be configured to direct flow of aliquid through the detection layer (or chromatographic membrane) in agenerally horizontal orientation, e.g., substantially along a singlehorizontal plane from a first end of the detection layer to the secondend of the detection layer. In other embodiments, the detection layercan be configured to direct flow of a liquid through the detection layerin a generally vertical orientation, e.g., substantially through aplurality of horizontal planes, for example, from the bottom of thedetecting layer to the top of the detecting layer, resulting in thelength of the fluid path being greater than the length of the apparatus.

In some examples, as a result of the length of the fluid path beinggreater than the length of the apparatus, the length of the apparatusmay be shortened without impeding the detection ability of theapparatus. In some cases, the length of the fluid path is from 5-10%greater than the length of the apparatus, from 10-20% greater than thelength of the apparatus, from 20-30% greater than the length of theapparatus, from 30-40% greater than the length of the apparatus, from50-75% greater than the length of the apparatus, from 75-100% greaterthan the length of the apparatus, or from 100-200% greater than thelength of the apparatus.

The apparatus can be positioned on the surface of an object. In someexamples, the apparatus can be positioned on, integrated in, orincorporated in an object. In other examples, the apparatus can bepositioned below, or below the surface of, an object. Suitable objectsinclude, for example, a natural fingernail, an artificial fingernail, alayer of fingernail polish, a fingernail sticker, a fingernail decal, acup, a drink coaster, a drink stirrer, a toothpick, a drink ornament(e.g., an umbrella), a pencil, a pen, a test strip, a sticker, a decal,a nail decal, a mesh nail wrap, or any other appropriate surface orstructure. In other embodiments, the apparatus may be positioneddirectly on skin, such as on a finger.

In some embodiments, the apparatus comprises a thickness ranging fromabout 0.2 micrometers (μm) to about 5 millimeters (mm). In someembodiments, the apparatus comprises a thickness ranging from about 20μm to about 5 mm. In some embodiments, the detection layer can have athickness of about 0.6 μm or less, 1 μm or less, 10 μm or less, 25 μm orless, 50 μm or less, 100 μm or less, 1 mm or less, 2 mm or less, 3 mm orless, 4 mm or less, or 5 mm or less.

In some embodiments, the apparatus comprises a length ranging from about0.5 mm to about 15 mm. In some embodiments, the apparatus comprises alength ranging from about 1 mm to about 10 mm, or from about 3 to about8 mm. In some embodiments, the detection layer can have a length ofabout 0.4 mm or less, 0.5 or less, 1 mm or less, 2 mm or less, 3 mm orless, 4 mm or less, 5 mm or less, 6 mm or less, 7 mm or less, 8 mm orless, 9 mm or less, 10 mm or less, 12 mm or less, or 15 mm or less.

In some embodiments, the apparatus comprises a width ranging from about0.5 mm to about 5 mm. In some embodiments, the apparatus comprises awidth ranging from about 1 mm to about 10 mm, or from about 3 to about 8mm. In some embodiments, the detection layer can have a width of about0.4 mm or less, 0.5 or less, 1 mm or less, 2 mm or less, 3 mm or less, 4mm or less, 5 mm or less, 6 mm or less, 7 mm or less, 8 mm or less, 9 mmor less, or 10 mm or less.

In some embodiments, the apparatus can be laminated to provideprotection from the external environment without compromising theintegrity of the test by permitting gas permeability during use.

Turning now to the Figures, FIG. 1 is an exploded cross-section view ofan apparatus 100 according to one embodiment described herein. Apparatus100 comprises a sample pad 110, a conjugate pad 120, a detection layer130 and an absorption pad or wick 160. The sample pad 110 is adjacent toa first portion 122 of the conjugate pad 120 so that in use a liquid isabsorbed into the conjugate pad 120 from the sample pad 110. A secondportion 124 of the conjugate pad is adjacent to the chromatographicmembrane 130 at a proximal end 132 of the chromatographic membrane 130so that in use a liquid is absorbed into the chromatographic membrane atthe proximal end 132 and moves through the chromatographic membranetoward the distal end 134 of the chromatographic membrane 130. Betweenthe proximal and distal ends the chromatographic membrane includes atleast one test line 140 where an analyte-conjugated protein is depositedand at least one control line 150 where an anti-species antibody isdeposited. The apparatus also comprises an absorption pad or wick 160adjacent to the chromatographic membrane 130 so that in use liquid isabsorbed into the wick from the chromatographic membrane 130. In someembodiments multiple test lines may be present to test for a pluralityof targeted substances. Optionally, the apparatus may have a clear coverlayer 170.

FIG. 2 is a cross-section view of an apparatus 200 according to oneembodiment described herein. Apparatus 200 comprises a combined samplepad-conjugate pad 250 which has a sample area 252 and a conjugate area254 that do not overlap. Apparatus 200 further comprises a detectionlayer 230 and a wick 260. The conjugate area 254 of the sample-conjugatepad 250 is adjacent to a first portion 232 of the detection layer 230 sothat in use a liquid is absorbed into the sample-conjugate pad 250,migrates into a proximal end 232 of the chromatographic membrane 230,and flows toward the distal end 234 of the chromatographic membrane 230.The apparatus also comprises an absorption pad or wick 260 adjacent tothe distal end 234 chromatographic membrane 230 so that in use a testliquid is absorbed into the wick from the chromatographic membrane 230.Optionally, the apparatus may have a clear cover layer 270.

In some embodiments, the sample pad is pretreated with a sample padbuffer solution. Pretreatment involves contacting the sample pad withthe sample pad buffer solution and then drying the sample pad. The driedsample pad comprises a residual buffer composition. In use, when a testliquid contacts the residual buffer composition, the buffer isreconstituted in the test liquid. In some embodiments, the sample padmay be pretreated with a sample pad buffer solution consistingessentially of biocompatible materials so that any potential interactionof the sample pad buffer ingredients with a beverage will not introducematerial unsuitable for ingestion into the beverage. In someembodiments, the sample pad buffer aids in neutralization of the acidicbeverages, and may also reduce the impact of other components, such ashigh sugar content, on test results. For purposes of this application,“sample pad buffer solution” and “sample area buffer solution may beused interchangeably.

In some embodiments, the sample pad buffer solution comprises potassiumcarbonate and/or calcium carbonate. In some embodiments, the sample padbuffer solution comprises a calcium salt of a weak acid.

In some embodiments the sample pad buffer solution comprises potassiumcarbonate. In some embodiments, potassium carbonate is present in thesample pad buffer solution in a concentration of from 200 to 3000millimolar (mM), from 500 to 2000 mM, from 750 to 1500 mM, from 0.8 to1.2 molar (M), from 0.9 to 1.1 M, or about 1 M. In some embodiments,potassium carbonate is present in the sample pad buffer solution in aconcentration of at least 800 mM, at least 900 mM, at least 1.0 M, atleast 1.1 M, at least 1.2 M, or at least 1.3 M. Optionally, in someembodiments, the sample pad buffer solution may comprise hydroxide,borate, and/or bicarbonate salts.

In some examples, the conjugate pad may be pretreated with conjugate padbuffer solution comprising a stabilizing agent and/or a shielding agent.Examples of stabilizing agents include saccharides such as sucrose,fructose, and trehalose. Examples of shielding agents include gelatin,casein, and BSA.

In some examples, the conjugate pad buffer solution comprises a buffersalt. Tris(hydroxymethyl) aminomethane (Tris) was found to beparticularly effective at neutralizing, and therefore mitigatingnegative effects, of acidic beverages on test results. In someembodiments, the conjugate pad buffer solution has a pH from 7.5 to 8.5,from 7.75 to 8.25, from 7.9 to 8.1, or about 7.8, about 8.0, or about8.2. Other buffer solutions, such as sodium borate buffer solutions, insome examples could not be prepared in concentrations high enough toprovide the necessary buffering capacity for the conjugate pad. Anusually high concentration of buffer solution is required due to the avery limited area (such as a 4×4 mm conjugate pad) to be impregnatedwith the conjugate pad buffer solution, which is dried, and then isreconstituted as the sample liquid flows through the conjugate pad. Insome embodiments, the conjugate pad buffer solution comprises Tris in aconcentration of from 0.4 to 0.6 molar (M), from 0.423 to 0.575 M, from0.45 to 0.55 M. In some embodiments, the conjugate pad buffer solutioncomprises Tris in a concentration of about 0.4 M, about 0.5 M, or about0.6 M.

In some embodiments, the conjugate pad buffer solution further comprisesone or more of a protein, a poly(vinylpyrrolidone), and a surfactant.Some non-limiting examples of surfactants are Aerosol OT, benzalkoniumchloride, BRIJ35, BRIJ 52, BRIJ98, CHEMAL-LA-9, Cremophore EL, IGEPALCA210, Merpol A, Pluronic F68, Pluronic F127, Pluronic L64, SilwetL7600, Surfactant 10G, Synperonic F108,2,4,7,9,-tetramethyl-5-decyn-4,7-diol ethoxylate, Tergitol, Tetronic90R4, Triton X-45, Triton X 100, Triton X-305, Tween-20, Tween-60, andTween-80. In some embodiments, the protein is BSA and thepoly(vinylpyrrolidone) is PVP-40. In some embodiments, the surfactantcomprises Triton X-100, Triton X-305 and/or Pluronic F68. In someexamples, BRIJ-98 was found to reduce background coloration caused bybeverages. Not intending to be bound by theory, BRIJ-98 causesprecipition of many colored red wine components. In some embodiments,the residual buffer composition can substantially reduce orsubstantially remove the appearance of colored components of a testliquid. “Substantially reduce or substantially reduce” means that thecolor of the test liquid does not interfere with the indication of testresults.

In some embodiments, the conjugate pad buffer composition is compatiblewith the anti-analyte antibody-particle conjugate, for example, theconjugate pad buffer composition, when reconstituted by the test liquid,does not denature the anti-analyte antibody-particle conjugate. Notintending to be bound by theory, this may be due to the high pH of theconjugate pad buffer and the resulting neutralization of acid in testliquids such as beverages.

The conjugate is not bound to the conjugate pad; rather, it is adheredor immobilized, so that the conjugate is released to the test liquid andflows with the test liquid across the chromatographic membrane. In someembodiments of the invention, the conjugate pad and the sample pad areformed from a single piece of material, such as nitrocellulose or awoven mesh of glass fibers or polyester fibers.

In some embodiments, the anti-analyte antibody-particle conjugate may beprepared from a commercially available monoclonal antibody and a gold ordye nanoparticle material. In some embodiments, the commerciallyavailable monoclonal antibody may be desalted using a spin column toreplace the antibody storage buffer with an antibody desalting buffer.In some embodiments, the antibody desalting buffer comprises a sodiumphosphate buffer. A sodium phosphate antibody desalting buffer may havea concentration of 5 mM, 10 mM, 25 mM, 50 mM, 75 mM, 100 mM, 125 mM, or150 mM, or from 50-150 mM, or from 75-125 mM, or from 90-110 mM. In someembodiments, the antibody desalting buffer may have a slightly basic pH,such as 7.2, 7.3, 7.4, 7.5, 7.6, 7.7, 7.8, 7.9, 8.0, 8.1, or 8.2. Whenthe antibody has been desalted and is dissolved in the antibodydesalting buffer, it may be conjugated with a gold or dye nanoparticlematerial. In some embodiments, the gold or dye nanoparticle material maybe dissolved or suspended in water with the pH adjusted to slightlybasic, such as pH 7.05, 7.1, 7.15, 7.2 or 7.25 by the addition of HCl orNaOH.

In some embodiments, after the antibody is dissolved in the antibodydesalting buffer and the gold or dye nanoparticle is dissolved orsuspended in slightly basic water, the two components are mixed, and aconjugation blocking buffer may be added to the resulting mixture. Insome embodiments, the conjugation blocking buffer comprises sodiumtetraborate, boric acid, and BSA. In some embodiments, the blockingbuffer can have a sodium tetraborate concentration of 10 mM, 25 mM, 50mM, 75 mM, or 100 mM, or from 10-110 mM, or from 25-75 mM, or from 45-55mM. In some embodiments, the conjugation blocking buffer may have abasic pH, such as 8.2, 8.4, 8.6, 8.8, 9.0, 9.2, 9.4, or 9.6. Theresulting anti-analyte antibody-particle conjugate may be isolated as apellet by centrifugation.

In some embodiments, the anti-analyte antibody-particle conjugate isapplied to the conjugate pad from a conjugate dilution buffer which maybe used to reconstitute the anti-analyte antibody-particle conjugatepellet. In some embodiments, the anti-analyte antibody-particleconjugate is dissolved in a conjugate dilution buffer prior todepositing the anti-analyte antibody-particle conjugate on the conjugatepad.

In some embodiments, the conjugate dilution buffer comprises a salt of aweak acid, a protein, and optionally, excipients such as saccharides. Insome embodiments, the conjugate dilution buffer comprises a borate, suchas sodium tetraborate, boric acid, BSA, and optionally, sucrose and/ortrehalose. In some examples, the conjugate dilution buffer comprises40-60 mM, 45-55 mM or about 50 mM borate, 1-3 weight percent (wt. %) BSA(e.g. 1 wt. %, 2 wt %, or 3 wt. %), 3-7 wt. % trehalose (e.g. 4 wt. %, 5wt %, or 6 wt. %), and 15-25 wt. % sucrose (e.g. 18 wt. %, 20 wt %, or22 wt. %). In some embodiments the conjugate dilution buffer has a pH offrom 8.5 to 9.5, (e.g. 8.7, 9.0, or 9.3). In some embodiments, the pH ofthe conjugate dilution buffer is titrated.

In some examples, the conjugate dilution buffer comprises 40-60 mM,45-55 mM or about 50 mM borate, 1-3 weight percent (wt. %) BSA (e.g. 1wt. %, 2 wt %, or 3 wt. %), and sucrose and/or trehalose are added afterthe conjugate has been dissolved in the conjugate dilution buffer. Insome embodiments, sucrose is added in an amount of 10%, 20%, or 30%,where 20% is determined, for example, according to the formula (volumeof conjugate in conjugate dilution buffer)(20 g sucrose)/(100 mL).Similarly, in some embodiments, trehalose is added in an amount of 3%,5%, or 7%, where 5% is determined, for example, according to the formula(volume of conjugate in conjugate dilution buffer)(5 g trehalose)/(100mL).

In some embodiments, any of the buffer solutions or buffer additivesdescribed herein has a viscosity of at least 10 cP. In otherembodiments, the buffer or buffer additives can comprise a viscosity ofat least 0.5 cP, at least 1 cP, at least 5 cP, at least 20 cP, at least30 cP, at least 60 cP, at least 80 cP, at least 100 cP, at least 1000cP, at least 20,000 cP, or at least 50,000 cP. In other embodiments, thebuffer or buffer additives can comprise a viscosity of between 0.5-2 cP,between 2-5 cP, between 5-20 cP, between 20-30 cP, between 30-60 cP,between 1-100 cP, between 2-80 cP, between 5-50 cP, between 10-1000 cP,between 10-20,000 cP, or between 10-50,000 cP. In some embodiments, thechromatographic membrane may be pretreated with a chromatographicmembrane buffer solution comprising 10-20 mM or 12-18 mM or about 15 mMsodium phosphate, 0.5-1.5 wt. % or 0.7 to 1.3 wt. %, or about 1 wt. %sucrose, 0.05-0.15 wt. % or 0.7 to 1.2 wt. % or about 1 wt. % BSA, and0.1-0.3 wt. % or about 0.2 wt. % PVP-40. In some embodiments, thechromatographic membrane buffer has a pH from 7.1 to 7.5. In someembodiments, the chromatographic membrane buffer may have a pH of 7.1,7.2, 7.3, 7.4, or 7.5, or from 7.1-7.5, or from 7.2 to 7.4, or from7.25-7.35.

The detection layer of certain embodiments described herein can providean visual indication or signal mechanism to a user as to whether aparticular compound is present. For example, the visual indication cancomprise the appearance, or lack thereof, of a colored dot, pattern, orregion; the printing of words, such as “SAFE,” “OK,” “YES,” or “NO”;checkmarks, emoticons or symbols such as a “

,” fluorescence, vibration, or sounds.

In some embodiments, the detection layer can provide an indication to auser by electrochemical detection. In some examples the detection layercan provide a device-aided quantitation, for example with the aid ofsmartphone application or other device. In some embodiments, thedetection layer can provide a semi-quantitative or quantitativeindication of the analyte in the liquid. In some examples, theindication of the analyte present in the liquid comprises a pattern oflines. For example, in one embodiment, 6 test lines may be placed on thedetection layer. When a direct immunoassay format is used, if theanalyte is present in certain quantities, one test line may developcolor. If the analyte is present in certain, larger quantities,additional test lines may develop color. If the analyte is present in aneven greater amount, all test lines may develop color.

Alternately, when an indirect immunoassay format is used, if the analyteis present in certain quantities, one test line may develop color. Ifthe analyte is present in certain, lesser quantities, additional testlines may develop color. If the analyte is present in an even lesseramount, all test lines may develop color. In some examples, during theassembly of the apparatus, the test line is deposited from a buffersolution in a low-to-high concentration gradient in the direction ofliquid flow across the chromatographic membrane to create a 2 mm testline with no leading edge effect. “Leading edge effect” refers to theformation of a color gradient at the test or control lines where thedarkest area is along the leading edge of the line and the color of theline become progressively lighter as it nears the distal edge. The“leading edge” of the test/control line is the side of the line whichcontacts the fluid first as it flows through the membrane.

In some embodiments, the detection layer comprises a thickness rangingfrom about 50 microns to about 1000 microns. In some embodiments, thedetection layer comprises a thickness ranging from about 200 microns toabout 400 microns. In some embodiments, the detection layer can have athickness of about 100 microns or less, 200 microns or less, 400 micronsor less, 600 microns or less, 800 microns or less, or 1000 microns orless.

In some embodiments, the detection layer can be configured to detect thepresence of a plurality of targeted substances. In some embodiments, thedetection layer can be physically divided to permit the detecting ofmultiple analytes without inferring with the detection of anotheranalyte. As another example, a detection layer can be multiplexed withcertain components to test for multiple analytes on a single detectionlayer. In some embodiments, the apparatus can include a plurality ofdiscrete, physical sections positioned adjacent to each other to make upa single detection layer. For example, a plurality of matrices can bepositioned side by side with each matrix configured to test for thepresence of a different compound in a liquid.

In some embodiments, the apparatus comprising a detection layer can alsoinclude at least one additional layer. In some embodiments, theapparatus can include at least one of a top laminate layer, a bottomlaminate layer, and a removable layer. In some embodiments, theapparatus can include any combination of layers described herein.

In some examples, an apparatus described herein includes a specificcombination of residual buffer formulations that can render theapparatus compatible with a wide range of test fluids. For example, afirst residual buffer formulation may be used at a location near thebeginning of the liquid flow path, for example the sample area, tointeract with components in the test fluid that could be detrimental totest results, such as acids, alcohol, and/or colorants, and a secondresidual buffer formulation may be used at a separate location furtherdown the liquid flow path to buffer the test liquid near a certain pH soas not to denature proteins involved in the assay.

In addition, a specific combination of buffer formulations can allowcombining multiple detection means (such as using two or moremarker-test line combinations) for detecting multiple analytes, whereasin the absence of the specific combination of residual bufferformulations the different detection means would not be compatible withthe same scope of test fluids. In one example, in the absence of aparticular residual buffer formulation, a first detection means fordetecting a first analyte is only compatible with test fluids A and B,and a second detection means for detecting a second analyte is onlycompatible with test fluids B and C. In that case, the first and secondmeans could not be used in combination to simultaneously detect thefirst and second analytes in fluids A and C. But a single apparatusincluding an appropriate combination of residual buffer formulations iscompatible with fluids A, B, and C, and can detect the first and thesecond analytes in all three fluids. This “multiplexing” is useful forthe detection of multiple analytes with may require different detectionmeans (such as different antibodies, aptamers, or markers) with a singleapparatus. In some examples, an apparatus described herein may detectthe presence of both benzodiazepines and ketamines.

Anti-Analyte Antibody Particle Conjugates

In some embodiments, the anti-analyte antibody-particle conjugatedescribed herein includes an anti-analyte antibody, a colorednanoparticle, and optionally one or more additional components.

An antibody is a large, Y-shaped protein produced mainly by plasma cellsthat is used by the immune system to identify and bind pathogens such asbacteria and viruses. Aptamers are oligonucleotide or peptide moleculesthat bind to a specific target molecule. The anti-analyte antibody oranti-analyte aptamer is an antibody or aptamer that is formed to bind aspecific analyte such as a drug molecule. As understood by a person ofordinary skill in the art, immunoassay techniques employ this “lock andkey” approach, using a specific antibody or aptamer to bind with atargeted substance.

Particles to enhance visibility and/or detection are frequently attachedto the anti-analyte antibody to increase visibility and/or detection ofthe anti-analyte antibody. Useful particles may comprise coloredcompounds or fluorescent compounds. In some embodiments, the particlecomprises fluorescein, Rose Bengal, derivatives and salts thereof, orcombinations thereof, or similar fluorophores. In other embodiments,nanoparticles are used as particles. The nanoparticle may be any colorednanoparticle such as gold and/or dye-infused polymer microbeads.

The anti-analyte antibody is joined, or conjugated, to the particle by alinker. The linker may be any linker that is not inconsistent with theobjectives of the current invention. Non-limiting examples of linkersare (N-(κ-maleimidoundecanoyloxy) sulfosuccinimide ester) (sulfo-KMUS),(succinimidyl-4-(N-maleimidomethyl)cyclohexane-1-carboxy-(6-amidocaproate))(LC-SMCC), N-(e-maleimidcCaproyloxy)-N-HydroxySuccinimide ester (KMUs),succinimidyl-4-(p-maleimidophenyl)butyrate (SMBP),(succinimidyl-6-((b-maleimidopropionamido)hexanoate) (SMPH),4-(N-maleimidomethyl)cyclohexanecarboxylic acid N-hydroxysuccinimideester (SMCC), 4-(N-maleimidomethyl)cyclohexane-1-carboxylic acid3-sulfo-N-hydroxysuccinimide ester sodium salt (sulfo-SMCC),(N-succinimidyl (4-iodoacetyl)aminobenzoate) (SIAB),N-(γ-maleimidobutyryloxy)sulfosuccinimide sodium salt (sulfo-GMBS),4-maleimidobutyric acid N-hydroxysuccinimide ester (GMBS), (succinimidyl3-(bromoacetamido)propionate) (SBAP), N-(2-carboxyethyl)maleimide(BMPA), N-α-maleimidoacet-oxysuccinimide ester (AMAS), N-succinimidyl3-(acetylthio)propionate (SATP), 3-maleimidobenzoic acidN-hydroxysuccinimide ester (MBS),(m-maleimidobenzoyl-N-hydroxysulfosuccinimide ester) (sulfo-MBS),N-ε-maleimidocaproic acid (EMCA), N-(ε-maleimidocaproyloxy)succinimide,N-succinimidyl 6-maleimidocaproate (EMCS), succinimidyl-(4-vinylsulfone)benzoate (SVSB), N-succinimidyl 3-maleimidopropionate (BMPS), orN-ethyl-N′-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDC). Insome embodiments, the gold nanoparticles are functionalized withcompounds such as 6-mercaptohexanoic acid, 8-mercaptooctanoic acid,12-mercaptododecanoic acids, or other mercapto-carboxylic acids.Reagents such as EDC may be used to couple the antibodies to thesereagents. Polymer microbeads may be functionalized with similarcarboxylic acids or amines.

The anti-analyte antibody-particle conjugate can be present in ananti-analyte antibody-particle conjugate composition in an amount offrom about 0.05 wt. % to about 10 wt. % (e.g., from about 0.5 wt. % toabout 8 wt. % or from about 0.8 wt. % to about 5 wt. %). For example,the anti-analyte antibody-particle conjugate can be present in theanti-analyte antibody-particle conjugate composition in an amount ofabout 10 wt. % or less, about 9.5 wt. % or less, about 9 wt. % or less,about 8.5 wt. % or less, about 8 wt. % or less, about 7.5 wt. % or less,about 7 wt. % or less, about 6.5 wt. % or less, about 6 wt. % or less,about 5.5 wt. % or less, about 5 wt. % or less, about 4.5 wt. % or less,about 4 wt. %, about 3.5 wt. % or less, about 3 wt. % or less, about 2.5wt. % or less, about 2 wt. % or less, about 1.5 wt. % or less, about 1wt. % or less, or about 0.5 wt. % or less. In some embodiments, theanti-analyte antibody-particle conjugate can be present in theanti-analyte antibody-particle conjugate composition in an amount ofabout 0.05 wt. %, about 0.1 wt. %, about 0.15 wt. %, about 0.2 wt. %,about 0.25 wt. %, about 0.3 wt. %, about 0.35 wt. %, about 0.4 wt. %,about 0.45 wt. %, about 0.5 wt. %, about 0.55 wt. %, about 0.6 wt. %,about 0.65 wt. %, about 0.7 wt. %, about 0.75 wt. %, about 0.8 wt. %,about 0.85 wt. %, about 0.9 wt. %, about 0.95 wt. %, about 1 wt. %,about 1.5 wt. %, about 2 wt. %, about 2.5 wt. %, about 3 wt. %, about3.5 wt. %, about 4 wt. %, about 4.5 wt. %, or about 5 wt. %.

A buffering agent can be present in the conjugate dilution buffer suchthat pH of the total marker composition is from about 5 to about 9(e.g., from about 6 to about 8 or from about 6.5 to about 7.5). Forexample, the buffering agent can be added to the composition to providea pH of about 5, about 5.5, about 6, about 6.5, about 7, about 7.5, orabout 8.

The composition can further include a solvent carrier. A suitablesolvent carrier includes water (e.g., deionized water). Optionally, thesolvent carrier can further include one or more organic solvents, suchas alcohols, glycols, and other liquids.

Analyte-Conjugate Protein

The analyte-conjugate protein comprises the analyte that is to bedetected conjugated or linked to a protein. Examples of suitableproteins are BSA, CRM197, KLH, thyroglobulin, tetanus toxoid, rabbitserum albumin, myoglobulins, tuberculin, poly-lysine, and/orpoly-glutamic acid.

Anti-Species Antibody

The anti-species antibody is capable of binding with the anti-analyteantibody-particle conjugate. Because the anti-species antibody will bindwith the anti-analyte antibody-particle conjugate whether or not ananalyte is present in the liquid, the location where the anti-speciesantibody has been deposited will develop color when the liquid containsan anti-analyte antibody-particle conjugate.

Chromatographic Membrane

As described above, the detection layer comprises a chromatographicmembrane. In some embodiments, the chromatographic membrane comprises,may consist essentially of, or may be formed from cellulose or cellulosederivatives, including surface-functionalized cellulose, glass fiber,and/or other materials. In some embodiments, the chromatographicmembrane comprises a porous chromatography medium. Typical pore size maycomprise a diameter of about 10 to 14 μm, although other size pores maybe used. The chromatography medium may be hydrophobic or hydrophilic,and may comprise inorganic powders such as silica, magnesium sulfate,and alumina; natural polymeric materials, particularly cellulosicmaterials and materials derived from cellulose, such as fiber containingpapers, for example, filter paper or chromatographic paper; synthetic ormodified naturally occurring polymers, such as nitrocellulose, celluloseacetate; poly(vinyl chloride), polyacrylamide, agarose, or polyacrylate;alone or in combination with other materials. Ceramics may also be used.Optionally, the chromatography medium can be bound to a backing layer.

Optionally, the chromatographic membrane may comprise one or morepolymers. Optionally, the one or more polymers includes polysaccharides.Suitable polysaccharides for use in the chromatographic membrane includeagar, agarose, alginate, carrageenan, cellulose, chitosan, dextran,konjac, and mixtures thereof. Exemplary agarose polymers include, forexample, carboxymethyl agarose, diethylaminoethyl agarose, and likederivatives. Optionally, the agarose polymers for use in thechromatographic membrane are commercially available from Pharmacia FineChemicals, Inc. (Piscataway, N.J.). Exemplary cellulose polymersinclude, for example, cellulose esters (e.g., cellulose acetate,cellulose acetate butyrate, cellulose acetate propionate), carboxymethylcellulose, diethylaminoethyl (DEAE) cellulose, nitrocellulose,phosphocellulose, quaternary ammonium substituted cellulose, andsulfoxyethyl cellulose. Optionally, the cellulose polymers for use inthe matrix are commercially available from Whatman Co. (Whatman PaperCo., Ltd., Maidstone, England) or BioRad Corp. (Richmond, Calif.). Insome embodiments, the chromatographic membrane includes glass fiber.Glass and polyester fiber may be acquired from Fusion 5 from GEHealthcare (GE Healthcare, Little Chalfont, UK).

The chromatographic membrane can further include an absorbent. Forexample, the absorbent can include chromatography paper, filter paper,and other materials typically used for chromatography, such as for paperchromatography or thin layer chromatography (TLC). The chromatographypaper and filter paper can be qualitative or quantitative filter paper,such as the chromatography paper and filter paper commercially availablefrom Whatman Co. (Whatman Paper Co., Ltd., Maidstone, England).

Optionally, the absorbent comprises silica gel, alumina, highperformance thin layer chromatography (HPTLC) silica gel, polysilicicacid, aluminum oxide, cellulose, polyamide, reversed phase silica gel C₂(dimethyl bonded), reversed phase silica gel C₂ (ethyl bonded), reversedphase silica gel C₈ (octyl bonded), reversed phase silica gel C₁₈(octadecyl bonded), acetylated cellulose, silica gel modified with aminogroups, silica gel modified with cyano groups, Kieselghur impregnatedwith hydrocarbons, anionic and cationic anion exchange resins,diethylaminoethyl cellulose, and mixtures of the listed sorbents. Theabsorbent can be immobilized on an inert surface.

Optionally, the chromatographic membrane can be pre-treated with adesiccant to integrate the desiccant into the chromatographic membrane.The desiccant can be any desiccant as known to those of skill in theart, including, but not limited to, molecular sieves, silica gels,clays, synthetic polymers, and starches. For example, suitabledesiccants include alumina, bauxite, anhydrous calcium sulfate,water-absorbing clays, silica gel, zeolite, and mixtures thereof.

Optionally, the chromatographic membrane can be pre-treated with abuffering agent, such as the buffering agents described above. Thematrix can be pre-treated with a buffering agent such that the matrix isbuffered at a pH ranging from about 3 to about 8 (e.g., from about 4 toabout 6 or from about 4.5 to about 5.5). For example, the bufferingagent can be added to the composition to provide a pH of about 3, about3.5, about 4, about 4.5, about 5, about 5.5, about 6, about 6.5, about7, about 7.5, or about 8.

The chromatographic membrane can be positioned on the surface of anobject. In some examples, the matrix can be positioned within an object.In other examples, the chromatographic membrane can be positioned belowthe surface of an object. Suitable objects include, for example, afingernail, an artificial fingernail, a layer of fingernail polish, afingernail sticker, a fingernail decal, a cup, a bar coaster, a drinkstirrer, a toothpick, a drink ornament (e.g., an umbrella), a pencil, apen, a test strip, a sticker, a decal, a nail decal, a mesh nail wrap,or any other appropriate surface. Other appropriate surfaces includeitems that could easily and discreetly be brought into contact with asuspect liquid, providing an improved degree of personal security forthe liquid consumer.

The apparatus described herein can also include a cover over thechromatographic membrane. The cover can be an opaque cover, a tintedcover, a transparent cover, or a translucent cover. Optionally, thecover can include one or more perforations. These perforations allow forthe escape of gaseous materials during the use of the apparatus. Inexamples where the cover is opaque, tinted, or translucent, the covercan optionally include one or more transparent windows on the cover. Thecover can be attached to the apparatus using any suitable bindingmaterial as known to those of skill in the art, including, for example,an adhesive. Suitable adhesives include but are not limited to acrylicand methacrylic ester homo- or copolymers, butyl rubber based systems,silicones, urethanes, vinyl esters and amides, olefin copolymermaterials, di-alkyl fumarates, natural or synthetic rubbers, and thelike, including hot-melt adhesives.

In some embodiments, the apparatus comprising a detection layer can alsoinclude at least one additional layer. In some embodiments, theapparatus can include at least one of a cover layer, a support layer,and a removable layer. In some embodiments, the apparatus can includeany combination of layers described herein.

In some embodiments, the detection layer comprises a lateral flow assay.In some embodiments, the lateral flow assay can rely on antibody-analyteinteractions to determine the presence of drugs in an alcoholic ornon-alcoholic beverage. In some embodiments, the lateral flow assay caninclude an anti-analyte antibody that is conjugated to colored particleswhich can be carried through a chromatographic membrane upon which aanalyte-conjugated protein (test line) and an anti-species antibody(control line) are immobilized.

In some embodiments, the lateral flow assay can have an extended storagelife. In some embodiments, the detection layer comprising a lateral flowassay (and apparatus) can be laminated to provide protection fromexternal environment without compromising the integrity of the test bypermitting gas permeability during use.

In some embodiments, a first indicator signals a portion of at least oneof a word, symbol, or character and a second indicator signals a portionof at least one of a word, symbol, or character. In some embodiments,the signal of the first indicator only signals to a user the presence ofthe targeted substance and wherein the signal of both the firstindicator and the second indicator signals to a user the absence of atargeted substance. Non-limiting embodiments include:

1. An apparatus for detecting the presence of an analyte in a liquid,the apparatus comprising a lateral flow assay capable of receiving asample of a beverage and analyzing the beverage for the presence of theanalyte.2. The embodiment of paragraph 1, wherein the apparatus comprises: asample area, a conjugate area, and a detection area, wherein at leastone of the sample area, conjugate area, or detection area comprises atleast one residual buffer composition.3. The embodiment of paragraph 2, wherein the conjugate area comprisesat least one anti-analyte antibody-particle conjugate or anti-analyteaptamer-particle conjugate; wherein the detection area comprises achromatographic membrane and at least one analyte-conjugate protein, andwherein the sample area is configured for receiving a liquid.4. The embodiment of paragraph 2 or 3, wherein the detection areafurther comprises at least one anti-species antibody or anti-speciesaptimer.5. The embodiment of any one of paragraphs 2-4, wherein the sample area,conjugate area, and the detection area are located on a single pad.6. The embodiment of any one of paragraphs 2-4, wherein at least one ofthe sample area, conjugate area, and the detection area is located on aseparate pad.7. The embodiment of any one of paragraphs 3-6, wherein thechromatographic membrane comprises one or more of cellulose,nitrocellulose, polyester fiber, and/or glass fiber.8. The embodiment of any one of paragraphs 1-7, further comprising acover defining a pattern, wherein the cover is disposed over thedetection area.9. The embodiment of any one of paragraphs 2-8, wherein the detectionarea is positioned on or within or under a natural fingernail, anartificial fingernail, a layer of fingernail polish, a fingernailsticker, a fingernail decal, a sticker, a cup, a drink coaster, a drinkstirrer, a toothpick, a drink ornament, a pencil, or a pen.10. The embodiment of any one of paragraphs 2-9, wherein the residualbuffer composition comprises at least one surfactant.11. The embodiment of paragraph 10, wherein the surfactant comprisesPluronic F-68, a fatty alcohol, a polyethylene glycol alkyl ether, apolypropylene glycol alkyl ether, a glucoside alkyl ether, polyethyleneglycol octyl, a glycerol alkyl ester, a phenyl ether, polyoxyethylene(20) oleyl ether, octylphenol ethoxylate, a polyethylene glycolalkylphenyl ether, polyethoxylated tallow amine,N,N-bis[3-(D-gluconamido)propyl]cholamide, polyoxyethylene (20) cetylether, dimethyldecylphosphine oxide, branched octylphenoxypoly(ethyleneoxy)ethanol, a polyoxyethylene-polyoxypropylene blockcopolymer, t-octylphenoxypolyethoxyethanol, polyoxyethylene (20)sorbitan monooleate, or a combination thereof.12. The embodiment of any one of paragraphs 2-11, wherein the residualbuffer composition comprises at least one buffer salt.13. The embodiment of paragraph 12 wherein the buffer salt comprisesmonosodium phosphate, disodium phosphate, sodium tetraborate,Tris(hydroxymethyl)methylaminopropanesulfonic (TAPS),N-cyclohexyl-2-aminoethanesulfonic acid (CHES),N-tris(hydroxymethyl)methyl-4-aminobutanesulfonic acid (TABS), bis-trismethane (Bis TRIS), tris(hydroxymethyl)aminomethane (TRIS),2-[[1,3-dihydroxy-2-(hydroxymethyl)propan-2-yl]amino]ethanesulfonic acid(TES), 2-(N-morpholino)ethanesulfonic acid (MES),N-(carbamoylmethyl)iminodiacetic acid (ADA),N-(2-acetamido)-2-aminoethanesulfonic acid (ACES), bis tris propane,piperazine-N,N′-bis(2-ethanesulfonic acid)(PIPES),N-(2-acetamido)-2-aminoethanesulfonic acid (ACES),3-morpholino-2-hydroxypropanesulfonic acid (MOPSO), cholamine chloride,(3-(N-morpholino)propanesulfonic acid) (MOPS),N,N-bis(2-hydroxyethyl)taurine (BES),N,N-bis(2-hydroxyethyl)-3-amino-2-hydroxypropanesulfonic acid (DIPSO),4-(N-morpholino)butanesulfonic acid (MOBS),3-[N-rris(hydroxymethyl)methylamino]-2-hydroxypropanesulfonic acid(TAPSO), acetamidoglycine, triethanolamine (TEA),piperazine-N,N′-bis(2-hydroxypropanesulfonic acid) POPSO,4-(2-hydroxyethyl)piperazine-1-(2-hydroxypropanesulfonic acid) hydrate(HEPPSO), 3-[4-(2-hydroxyethyl)-1-piperazinyl]propanesulfonic acid(HEPPS), tricine, tris(hydroxymethyl)aminomethane, trometamol (TRIZMA),glycinamide, glycyl-glysine,N-(2-hydroxyethyl)piperazine-N′-(4-butanesulfonic acid) (HEPBS), bicine,2-amino-2-methyl-1-propanol (AMP),N-(1,1-dimethyl-2-hydroxyethyl)-3-amino-2-hydroxypropanesulfonic acid(AMPSO), N-cyclohexyl-2-hydroxyl-3-aminopropanesulfonic acid (CAPSO),N-cyclohexyl-3-aminopropanesulfonic acid (CAPS),4-(cyclohexylamino)-1-butanesulfonic acid (CABS), and(4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid) (HEPES), carnitine,gamma-aminobutyric acid, taurine, or salts of amino acids alanine,arginine, asparagine, aspartic acid, cysteine, glutamic acid, glutamine,glycine, histidine, isoleucine, leucine, lysine, methionine,phenylalanine, proline, serine, threonine, tryptophan, tyrosine, orvaline.14. The embodiment of any one of paragraphs of claims 2-13, wherein thesample area comprises a residual sample area buffer composition, andwherein the residual sample area buffer composition comprises apotassium salt of a weak acid and at least one surfactant.15. The embodiment of any one of paragraphs 2-14, wherein the conjugatearea comprises a residual conjugate area buffer composition, and whereinthe residual conjugate area buffer composition comprises a Good's buffersalt and one or more of a protein, an oligomer, a polymer, and asurfactant.16. The embodiment of any one of paragraphs 2-15, wherein the detectionarea comprises a residual chromatographic membrane buffer composition,and wherein the residual chromatographic membrane buffer compositioncomprises a phosphate salt and one or more of a saccharide, a protein,an oligomer, and a polymer.17. The embodiment of any one of paragraphs 2-16, wherein the lateralflow assay is configured to detect multiple analytes.18. The embodiment of any one of paragraphs 2-17, wherein the residualbuffer composition can reduce the acidity of a test liquid.19. The embodiment of any one of paragraphs 2-18, wherein the residualbuffer composition can increase the viscosity of a test liquid.20. The embodiment of any one of paragraphs 2-19 wherein the residualbuffer composition can substantially reduce or substantially remove theappearance of colored components of a test liquid.21. A method of detecting an analyte in a liquid, said methodcomprising: providing the apparatus of any one of claims 1-20; exposinga portion of the apparatus to the liquid; and observing a visualindication to determine presence or absence of the analyte.22. The embodiment of paragraph 21, wherein the liquid is a beverage.23. The embodiment of paragraph 21, wherein the liquid is a foodextract.24. The embodiment of any one of paragraphs 21-23, wherein the liquidhas a pH from about 4.5 to about 6.8.25. A method of making an apparatus for detecting the presence of ananalyte in a liquid, the method comprising: applying a buffer solutionto at least one of a conjugate pad comprising a conjugate areacomprising at least one anti-analyte antibody-particle conjugate oranti-analyte aptamer-particle conjugate; a detection area comprising achromatographic membrane and an analyte-conjugate protein; or a samplearea for receiving a liquid; drying the buffer solution; and assemblingthe conjugate pad, detection area, sample area and a wick so that thesample area is in contact with a portion of the conjugate area, anotherportion of the conjugate area is in contact with a proximal end of thedetection area, and the wick is in contact with a distal end of thedetection area.

The apparatus and methods of the appended claims are not limited inscope by the specific apparatus and methods described herein, which areintended as illustrations of a few aspects of the claims and anyapparatus and methods that are functionally equivalent are intended tofall within the scope of the claims. Various modifications of theapparatus and methods in addition to those shown and described hereinare intended to fall within the scope of the appended claims. Forexample, additional specific embodiments of apparatus, systems, andmethods consistent with the present apparatus and methods are describedand set forth in a PCT patent application entitled “Apparatus, System,and Method for Detecting a Target Substance,” applied for by UndercoverColors, Inc. and filed on the same day as the present application, whichis incorporated by reference in its entirety.

Further, while only certain representative apparatus materials andmethod steps disclosed herein are specifically described, othercombinations of the apparatus materials and method steps also areintended to fall within the scope of the appended claims, even if notspecifically recited. Thus, a combination of steps, elements,components, or constituents may be explicitly mentioned herein; however,other combinations of steps, elements, components, and constituents areincluded, even though not explicitly stated. The term “comprising” andvariations thereof as used herein is used synonymously with the term“including” and variations thereof and are open, non-limiting terms.Although the terms “comprising” and “including” have been used herein todescribe various embodiments, the terms “consisting essentially of” and“consisting of” can be used in place of “comprising” and “including” toprovide for more specific embodiments of the invention and are alsodisclosed.

EXAMPLES Example 1: Lateral Flow Immunoassay

A lateral flow immunoassay of the invention was prepared as follows. Abenzo test line solution was prepared using (Benzodiazepine-BSA, 5:1ratio) solution diluted to 2 mg/mL with pH 7.4 Phosphate Buffered Saline(lx). A benzo control line solution was prepared using Goat Anti-MouseAntibody solution diluted to 1 mg/mL with pH 7.4 Phosphate BufferedSaline (lx). A test line of the diluted benzo test line solution wasprinted 12 mm from the bottom of the FF120HP (GE Healthcare)nitrocellulose strip, which has a capillary rise time of about 120seconds for 4 cm. A control line of diluted benzo control line solutionwas printed 1.5 mm above the test line. The printed strip was placed ina forced air oven to dry for 60 minutes at 10% humidity and 37° C., andthen it was stored in a desiccator at 20% humidity until used. Theprinted FF120HP nitrocellulose strip was treated with the AbcamImmunoassay Buffer (BSA Free), and was placed in a forced air oven todry for 60 minutes at 10% humidity and 37° C., and then it was stored ina desiccator at 20% humidity until used.

Monoclonal Mouse Anti-Benzodiazepine Antibody-Gold NP conjugate wasprepared by first desalting the Monoclonal Mouse Anti-BenzodiazepineAntibody solution using a Zeba spin columns (Thermo Scientific, PN:89882) to replace the stock buffer with 100 mM, pH 7.4 sodium phosphatebuffer. The desalted Monoclonal Mouse Anti-Benzodiazepine Antibodysolution in PBS was then conjugated to 40 nm colloidal goldnanoparticles in 50 mM Sodium Borate Buffer. During the conjugationprocess the 5 mM Sodium Borate buffer with 5% BSA is added to theconjugation solution. Upon completion of the conjugation of theMonoclonal Mouse Anti-Benzodiazepine Antibody to the 40 nm gold NP, theMonoclonal Mouse Anti-Benzodiazepine Antibody-Gold NP conjugate wasconcentrated and subsequently diluted to OD10 with 100 mM Sodium Boratebuffer containing 0.5% Fish Skin Gelatin and 0.1% Tween 80.

A conjugate pad was prepared by pretreating a strip of Ahlstrom 8964glass fiber pad with 50 mM Sodium Borate containing 1% BSA, 5% Sucrose,2% Trehalose, 0.25% Tween 20, and 0.15M KCl, and then the pretreated6614 strip was placed in a forced air oven for 60 minutes at 10%humidity and 37° C., and then stored in a desiccator at 20% humidityuntil used. The buffered diluted conjugate solution was printedcontinuously across the 8864 strip at a rate of 8 uL per centimeter, andthen the strip was placed in a forced air oven for 60 minutes at 10%humidity and 40° C., and then stored in a desiccator at 20% humidity.

To prepare the sample pad a strip of CF4 (GE Healthcare) was treatedwith 1M K₂CO₃, and then the strip was placed in a forced air oven for 60minutes at 10% humidity and 40° C., and then stored in a desiccator at20% humidity. The master card was assembled by applying a printed stripof nitrocellulose to an adhesive backing. The conjugate pad was appliedso as to achieve an overlap of 2 mm with the bottom of thenitrocellulose. The sample pad was applied so as to achieve an overlapof 2 mm with the bottom of the conjugate pad. An Ahlstrom 319 wickingpad was applied as to achieve an overlap of 2 mm with the top of thenitrocellulose. The master card was then cut into 4 mm wide strips.

Example 2: Preparation of Buffer Solutions

Buffer solutions were prepared as follows:

Antibody Desalting Buffer Solution:

A 100 mM sodium phosphate, pH 7.5 buffer was prepared by combining, inorder:Molecular Biology Reagent Water (Sigma, PN: W4502) was added in theamount of: 80% of total batch volumeSodium phosphate monobasic (Sigma, PN: S3139) was added in the amountof: 10.2 g/L×batch volume (L)Sodium phosphate dibasic (Sigma, PN: S9763 was added in the amount of:58.91 g/L×batch volume (L)Molecular Biology Reagent Water (Sigma, PN: W4502) to final volume pHwas adjusted to 7.5 using NaOH or concentrated HCl.

Conjugation Blocking Buffer Solution:

A 50 mM sodium borate, 10% BSA, pH 9.0 buffer was prepared by combining,in order:Sodium tetraborate decahydrate (Fisher, PN: AC41945-0010): 11.4 g/LBoric acid (Fisher, PN: A74-1): 1 g/LBovine serum albumin (BSA, Equitech, PN: BAH64): 100 g/LMolecular Biology Reagent Water (Sigma, PN: W4502) to final volumepH was adjusted to 9.0 using NaOH or HCl, and then the buffer wasfiltered using a 0.2 μm filter (VWR, PN: 73520-994).

Conjugate Dilution Buffer Solution:

A 50 mM sodium borate, 1% BSA, 5% trehalose, and 20% sucrose, pH 9.0buffer was prepared by combining, in order:

-   -   a. Sodium tetraborate decahydrate (Fisher, PN: AC41945-0010):        11.4 g/L    -   b. Boric acid (Fisher, PN: A74-1): 1 g/L    -   c. Bovine serum albumin (BSA, Equitech, PN: BAH64): 10 g/L    -   d. Sucrose (Sigma, PN: 84097)    -   e. Trehalose (Sigma, PN: 90210)    -   f. Molecular Biology Reagent Water (Sigma, PN: W4502) to final        volume

Chromatographic Membrane Buffer Solution:

A 10 mM sodium phosphate, 0.1% sucrose, 0.1% BSA, 0.2% PVP-40, pH 7.5buffer was prepared by combining, in order,per liter of buffer:Sodium phosphate monobasic (Sigma, PN: S3139), 0.204 gSodium phosphate dibasic (Sigma, PN: S9763), 1.178 g

Sucrose (Sigma, PN: 84097) 1.0 g

Bovine serum albumin (BSA, Equitech, PN: BA H64). 1.0 g

Poly(vinylpyrrolidone)-40 (PVP-40, Sigma, PN: PVP-40): 2.0 g

Molecular Biology Reagent Water (Sigma, PN: W4502) to one liter.pH was adjusted to 7.2 using NaOH or HCl, and then the buffer wasfiltered using a 0.2 μm filter (VWR, PN: 73520-994).

Conjugate Pad Buffer Solution:

A 0.5 M Tris, 3% BSA, 1% PVP-40, 0.25% Triton X-100, 0.5% Pluronic F-68,pH 8.0 buffer was pre prepared by combining, in order:Tris base (Sigma, PN: T1375): 114.8 g/LBovine serum albumin (BSA, Equitech, PN: BAH64): 30 g/L

Polyvinylpyrrolidone-40 (PVP-40, Sigma, PN: PVP-40): 10 g/L Triton X-100(Sigma, PN: T8787): 2.5 g/L Pluronic F-68 (Thermo Fisher, PN: 24040032):5 g/L

Add Molecular Biology Reagent Water (Sigma, PN: W4502) to final volume

Sample Area Buffer Solution:

A 1.0 M Potassium Carbonate (K₂CO₃) buffer with 0.25% Triton X-305, pH7.0 buffer was pre prepared by combining, in order:Potassium carbonate (Sigma PN: P1472): 138.2 g/L

Triton X-305 (Sigma, PN: X305): 3.6 g/L

Add Molecular Biology Reagent Water (Sigma, PN: W4502) to final volume

Example 3: Preparation of a Lateral Flow Assay with a CombinedSample-Conjugate Pad

A lateral flow immunoassay of the invention was prepared as follows. Abenzo test line solution was prepared using (Benzodiazepine-BSA, 5:1ratio) solution diluted to 4 mg/mL with pH 7.4 Phosphate Buffered Saline(lx). A benzo control line solution was prepared using Goat Anti-MouseAntibody solution diluted to 1 mg/mL with pH 7.4 Phosphate BufferedSaline (lx). A test line of the diluted benzo test line solution wasprinted 5 mm from the bottom of the 8 mm wide CN095 (Sartorius)nitrocellulose strip, which has a capillary rise time of about 85±10seconds for 4 cm. A control line of diluted benzo control line solutionwas printed 2 mm above the test line. The printed strip was placed in aforced air oven to dry for 30 minutes at 10% humidity and 40° C., andthen it was stored for 16 hours in a desiccator at 20% humidity. Theprinted CN095 nitrocellulose strip (Sartorius) was treated with theChromatographic Membrane Buffer described above in Example 2, and wasplaced in a forced air oven to dry for 30 minutes at 10% humidity and40° C., and then it was stored for 16 hours in a desiccator at 20%humidity.

Monoclonal Mouse Anti-Benzodiazepine Antibody-Gold NP conjugate wasprepared by first desalting the Monoclonal Mouse Anti-BenzodiazepineAntibody solution using a Zeba spin columns (Thermo Scientific, PN:89882) to replace the stock buffer with 100 mM, pH 7.4 sodium phosphatebuffer. The desalted Monoclonal Mouse Anti-Benzodiazepine Antibodysolution in PBS was then conjugated to 40 nm colloidal goldnanoparticles. During the conjugation process the Conjugation BlockingBuffer is added to the conjugation solution. Upon completion of theconjugation of the Monoclonal Mouse Anti-Benzodiazepine Antibody to the40 nm gold NP, the Monoclonal Mouse Anti-Benzodiazepine Antibody-Gold NPconjugate was concentrated and subsequently diluted to OD15 with theConjugate Dilution Buffer as described above in Example 2.

A combined sample-conjugate pad was prepared by pretreating a strip ofAhlstrom 6614 polyester fiber pad with Conjugate Pad Buffer describedabove in Example 2, and then the pretreated 6614 strip was placed in aforced air oven for 60 minutes at 10% humidity and 40° C., and thenstored for 16 hours in a desiccator at 20% humidity. To prepare thesample area of the combined sample-conjugate pad, only the sample areaof an Ahlstrom 6614 polyester fiber pad was treated with the Sample AreaBuffer described above in Example 2. The buffered diluted conjugatesolution was printed continuously across the strip on 6614 in only theconjugate area at a rate of 5 per centimeter, and then the strip wasplaced in a forced air oven for 60 minutes at 10% humidity and 40° C.,and then stored for 16 hours in a desiccator at 20% humidity.

The master card was assembled by applying a printed strip ofnitrocellulose to an adhesive backing. The sample/conjugate pad wasapplied so as to achieve an overlap of 2 mm with the bottom of thenitrocellulose. An Ahlstrom 319 wicking pad was applied as to achieve anoverlap of 2 mm with the top of the nitrocellulose. The master card wasthen cut into 4 mm wide strips.

Example 4: The Effect of K₂CO₃ and TRIS Sample Pad Treatment on LateralFlow Assay Results

Lateral flow assays were prepared by the process of Example 3, exceptthat the assays of Table 1 had no sample pad/area pretreatment, and theassays of Table 2 were pretreated with a sample area buffer solutioncomprising potassium carbonate. A check indicates no assay failure. An Xequals false negative results due to non-specific binding of conjugateto test line. The false negative results were overcome by pre-treatment,with one exception of hot coffee.

Procedure:

1.) Prepare assays according to the procedure described in Example 3.Prepare half of the assays without the addition of the Sample AreaBuffer.

2.) Prepare individual spiked solutions of each beverage listed. Thebeverages are spiked with either Alprazolam, Diazepam, or Flunitrazepamto a final concentration of 1000 ng/mL.

3.) Deposit 20 μL of the designated blank beverage on the untreatedsample area of three assays per designated beverage and record theresults at 1 minute.

4.) Deposit 20 μL of the designated spiked beverage on the untreatedsample area of three assays per designated beverage and record theresults at 1 minute.

5.) Deposit 20 μL of the designated blank beverage on the treated samplearea of three assays per designated beverage and record the results at 1minute.

6.) Deposit 20 μL of the designated spiked beverage on the treatedsample area of three assays per designated beverage and record theresults at 1 minute.

TABLE 1 No potassium carbonate pre-treatment of sample pad/area. ValiumXanax Rohypnol (diazepam) (alprazolam) (flunitrazepam) Beer/ Sam AdamsBoston Lager ✓ ✓ ✓ Other Guinness ✓ ✓ ✓ Blue Moon ✓ ✓ ✓ Big Boss BadPenny ✓ ✓ ✓ Lonerider Shotgun Betty ✓ ✓ ✓ Hefeweizen Foothills People'sPorter ✓ ✓ ✓ Duck-Rabbit Amber ✓ ✓ ✓ Sweetwater IPA ✓ ✓ ✓ Sierra NevadaPale Ale ✓ ✓ ✓ Bell's Oberon ✓ ✓ ✓ Mike's Hard Lemonade X X X AngryOrchard Cider X X X White Yellowtail Pinot Grigio X ✓ ✓ Wine BarefootMoscato X X X Gallo Chardonnay ✓ ✓ ✓ Mondavi Woodbridge X X X SauvignonBlanc Barefoot Riesling X X ✓ Rose Gallo White Merlot X X X Wine SutterHome Pink Moscato X ✓ X Yellowtail Pink Moscato X X X Barefoot RedMoscato ✓ ✓ ✓ Mondavi Woodbridge X X X White Zinfandel Red YellowtailMerlot X X X Wine Sutter Home Pinot Noir X X X Barefoot Shiraz ✓ ✓ ✓Mondavi Woodbridge ✓ ✓ ✓ Zinfandel Gallo Cabernet Sauvignon ✓ ✓ ✓ MixedRum and Coke ✓ ✓ ✓ Drinks Martini ✓ ✓ ✓ Mojito X X X Old Fashioned ✓ ✓ ✓Long Island Iced Tea X X X White Russian ✓ ✓ ✓ Pina Colada ✓ ✓ ✓ JoseCuervo Ready to Drink ✓ ✓ ✓ Classic Margarita Screwdriver ✓ ✓ ✓Cosmopolitan ✓ ✓ ✓ Tequila Sunrise ✓ ✓ ✓ Margarita X X X Daiquiri X X XIrish Coffee X X X Bloody Mary ✓ ✓ ✓ Liquor Smirnoff Vodka ✓ ✓ ✓ CaptainMorgan Spiced ✓ ✓ ✓ Rum Jack Daniel's Whiskey ✓ ✓ ✓ Jagermeister ✓ ✓ ✓Tanqueray Gin X X X Bacardi Rum ✓ ✓ ✓ Crown Royal Whisky X X X Jim BeamBourbon ✓ ✓ ✓ Jose Cuervo Tequila ✓ ✓ ✓ Fireball Cinnamon Whisky ✓ ✓ ✓Dekuyper Peachtree ✓ ✓ ✓ Malibu Coconut Rum ✓ ✓ ✓ Mixers Cranberry Juice✓ ✓ ✓ Lemonade ✓ X X Hawaiian Punch ✓ ✓ ✓ Half and Half ✓ ✓ ✓ Coffee(hot) X X X Orange Juice ✓ ✓ ✓ Rose's Mojito Mix X X X Tonic Water ✓ ✓ ✓Pineapple Juice X X X Coke ✓ ✓ ✓ V8 ✓ ✓ ✓ Club Soda ✓ ✓ ✓ Lime Juice X XX

TABLE 2 With potassium carbonate pre-treatment of sample pad/area.Valium Xanax Rohypnol (diazepam) (alprazolam) (flunitrazepam) Beer/ SamAdams Boston Lager ✓ ✓ ✓ Other Guinness ✓ ✓ ✓ Blue Moon ✓ ✓ ✓ Big BossBad Penny ✓ ✓ ✓ Lonerider Shotgun Betty ✓ ✓ ✓ Hefeweizen FoothillsPeople's Porter ✓ ✓ ✓ Duck-Rabbit Amber ✓ ✓ ✓ Sweetwater IPA ✓ ✓ ✓Sierra Nevada Pale Ale ✓ ✓ ✓ Bell's Oberon ✓ ✓ ✓ Mike's Hard Lemonade ✓✓ ✓ Angry Orchard Cider ✓ ✓ ✓ White Yellowtail Pinot Grigio ✓ ✓ ✓ WineBarefoot Moscato ✓ ✓ ✓ Gallo Chardonnay ✓ ✓ ✓ Mondavi Woodbridge ✓ ✓ ✓Sauvignon Blanc Barefoot Riesling ✓ ✓ ✓ Rose Gallo White Merlot ✓ ✓ ✓Wine Sutter Home Pink Moscato ✓ ✓ ✓ Yellowtail Pink Moscato ✓ ✓ ✓Barefoot Red Moscato ✓ ✓ ✓ Mondavi Woodbridge White ✓ ✓ ✓ Zinfandel RedYellowtail Merlot ✓ ✓ ✓ Wine Sutter Home Pinot Noir ✓ ✓ ✓ BarefootShiraz ✓ ✓ ✓ Mondavi Woodbridge ✓ ✓ ✓ Zinfandel Gallo Cabernet Sauvignon✓ ✓ ✓ Mixed Rum and Coke ✓ ✓ ✓ Drinks Martini ✓ ✓ ✓ Mojito ✓ ✓ ✓ OldFashioned ✓ ✓ ✓ Long Island Iced Tea ✓ ✓ ✓ White Russian ✓ ✓ ✓ PinaColada ✓ ✓ ✓ Jose Cuervo Ready to Drink ✓ ✓ ✓ Classic MargaritaScrewdriver ✓ ✓ ✓ Cosmopolitan ✓ ✓ ✓ Tequila Sunrise ✓ ✓ ✓ Margarita ✓ ✓✓ Daiquiri ✓ ✓ ✓ Irish Coffee ✓ ✓ ✓ Bloody Mary ✓ ✓ ✓ Liquor SmirnoffVodka ✓ ✓ ✓ Captain Morgan Spiced ✓ ✓ ✓ Rum Jack Daniel's Whiskey ✓ ✓ ✓Jagermeister ✓ ✓ ✓ Tanqueray Gin ✓ ✓ ✓ Bacardi Rum ✓ ✓ ✓ Crown RoyalWhisky ✓ ✓ ✓ Jim Beam Bourbon ✓ ✓ ✓ Jose Cuervo Tequila ✓ ✓ ✓ FireballCinnamon Whisky ✓ ✓ ✓ Dekuyper Peachtree ✓ ✓ ✓ Malibu Coconut Rum ✓ ✓ ✓Mixers Cranberry Juice ✓ ✓ ✓ Lemonade ✓ ✓ ✓ Hawaiian Punch ✓ ✓ ✓ Halfand Half ✓ ✓ ✓ Coffee (hot) X X X Orange Juice ✓ ✓ ✓ Rose's Mojito Mix ✓✓ ✓ Tonic Water ✓ ✓ ✓ Pineapple Juice ✓ ✓ ✓ Coke ✓ ✓ ✓ V8 ✓ ✓ ✓ ClubSoda ✓ ✓ ✓ Lime Juice ✓ ✓ ✓

Example 5: Faster Development of Test Results in Inventive Assays Vs.Comparative Assays

Lateral flow assays were prepared by the process of Example 3 and werecompared to commercial lateral flow assays (DBZ-114 distributed byInnovacon, San Diego, Calif.) 30 seconds after exposure to a test fluid.The inventive assay results are fully developed by 30 seconds, whereasthe comparative assays had not fully developed at 30 seconds.

Procedure:

1.) Prepare assays according to the procedure described in Example 3. Toprepare linear assays use a rectangular Ahlstrom 319 wick. To prepareminiaturized assays use the U-shaped Ahlstrom 319 wick.2.) Arrange the miniaturized and linear assays on the testing sheet.3.) Deposit 20 μL of blank Corona beer on the sample area of the linearassays marked blank.4.) Deposit 20 μL of Corona beer spiked with 1000 ng/mL Flunitrazepam onthe sample area of the linear assays.5.) Deposit 20 μL of blank Corona beer on the sample pad of the U-wickassays marked blank.6.) Deposit 20 μL of Corona beer spiked with 1000 ng/mL Flunitrazepam onthe sample pad of the U-wick assays.7.) Take picture at 30 seconds

Results are shown in FIG. 3 with the lateral flow assays prepared byExample 3 shown on the left and the commercial lateral flow assays shownon the right.

Example 6: Beverage Components Cause False Negative Results inComparative Assays, but not in Inventive Assays

Comparative commercial assays as used in Example 5 fail (due to falsenegatives) in whiskey and moscato after 5 minutes of development due tospecifications of the commercial assay. The commercial assay completelyfails to run in daiquiri, and no results are visible after 5 minutes.The inventive assays (prepared as in Example 3) perform successfully inall cases, with no false negative results.

Procedure:

1.) Prepare miniature assays according to the procedure described inExample 3.2.) Arrange the miniaturized and commercial assays on the testing sheet.3.) Deposit 20 μL of the designated blank beverage on the sample area ofthe miniature assays marked blank.4.) Deposit 20 μL of designated beverage spiked with 1000 ng/mLFlunitrazepam on the sample area of the miniature assays.5.) Deposit 100 μL of designated blank beverage on the sample pad of thecommercial assays marked blank.6.) Deposit 100 μL of designated beverage with 1000 ng/mL Flunitrazepamon the sample pad of the commercial assays.7.) Take picture at 5 minutes to allow time for the commercial assays tofully develop.

Results are shown in FIG. 4 for daiquiri, whisky, and water, and in FIG.5 for Corona, orange juice, and moscato, with the six commercial assayson top and the six inventive assays on the bottom in both Figures.

Example 7: U-Shaped Wick Shortens Assay Length without AffectingPerformance

Inventive assays (prepared as in Example 3) with a U-shaped wick (shownon right), where the fluid path is longer than the assay length, performjust as well as inventive assays (prepared as in Example 3) with alinear wick (shown on left), where the fluid path equals the assaylength.

Procedure:

1.) Prepare assays according to the procedure described in Example 3. Toprepare linear assays use a rectangular Ahlstrom 319 wick. To prepareminiaturized assays use the U-shaped Ahlstrom 319 wick.2.) Arrange the miniaturized and linear assays on the testing sheet.3.) Deposit 20 μL of blank Corona on the sample area of the linearassays marked blank.4.) Deposit 20 μL of Corona spiked with 1000 ng/mL Flunitrazepam on thesample area of the linear assays.5.) Deposit 20 μL of blank Corona on the sample pad of the U-wick assaysmarked blank.6.) Deposit 20 μL of Corona spiked with 1000 ng/mL Flunitrazepam on thesample pad of the U-wick assays.7.) Take picture at 30 seconds

Results are shown in FIG. 6 with the U-shaped wick assays on the rightand the linear wick assays on the left.

1. An apparatus for detecting the presence of an analyte in a liquid,the apparatus comprising a lateral flow assay capable of receiving asample of a beverage and analyzing the beverage for the presence of theanalyte.
 2. The apparatus of claim 1, wherein the lateral flow assaycomprises: a sample area, a conjugate area, and a detection area,wherein at least one of the sample area, conjugate area, or detectionarea comprises at least one residual buffer composition.
 3. Theapparatus of claim 2, wherein the conjugate area comprises at least oneanti-analyte antibody-particle conjugate or anti-analyteaptamer-particle conjugate; wherein the detection area comprises achromatographic membrane and at least one analyte-conjugate protein, andwherein the sample area is configured for receiving a liquid.
 4. Theapparatus of claim 2, wherein the detection area further comprises atleast one anti-species antibody or anti-species aptamer.
 5. Theapparatus of claim 2, wherein the sample area, conjugate area, and thedetection area are located on a single pad.
 6. The apparatus of claim 2,wherein at least one of the sample area, conjugate area, and thedetection area is located on a separate pad.
 7. The apparatus of claim3, wherein the chromatographic membrane comprises one or more ofcellulose, nitrocellulose, polyester fiber, and/or glass fiber.
 8. Theapparatus of claim 2, wherein the apparatus further comprises a coverdefining a pattern, wherein the cover is disposed over the detectionarea.
 9. The apparatus of claim 2, wherein the detection area ispositioned on or within or under a natural fingernail, an artificialfingernail, a layer of fingernail polish, a fingernail sticker, afingernail decal, a sticker, a cup, a drink coaster, a drink stirrer, atoothpick, a drink ornament, a pencil, or a pen.
 10. The apparatus ofclaim 2, wherein the residual buffer composition comprises at least onesurfactant.
 11. The apparatus of claim 10, wherein the surfactantcomprises a poloxamer, a fatty alcohol, a polyethylene glycol alkylether, a polypropylene glycol alkyl ether, a glucoside alkyl ether,polyethylene glycol octyl, a glycerol alkyl ester, a phenyl ether,polyoxyethylene (20) oleyl ether, octylphenol ethoxylate, a polyethyleneglycol alkylphenyl ether, polyethoxylated tallow amine,N,N-bis[3-(D-gluconamido)propyl]cholamide, polyoxyethylene (20) cetylether, dimethyldecylphosphine oxide, branched octylphenoxypoly(ethyleneoxy)ethanol, a polyoxyethylene-polyoxypropylene blockcopolymer, t-octylphenoxypolyethoxyethanol, polyoxyethylene (20)sorbitan monooleate, or a combination thereof.
 12. The apparatus ofclaim 2, wherein the residual buffer composition comprises at least onebuffer salt.
 13. The apparatus of claim 12, wherein the buffer saltcomprises monosodium phosphate, disodium phosphate, sodium tetraborate,Tris(hydroxymethyl)methylaminopropanesulfonic (TAPS),N-cyclohexyl-2-aminoethanesulfonic acid (CHES),N-tris(hydroxymethyl)methyl-4-aminobutanesulfonic acid (TABS), bis-trismethane (Bis TRIS), tris(hydroxymethyl)aminomethane (TRIS),2-[[1,3-dihydroxy-2-(hydroxymethyl)propan-2-yl]amino]ethanesulfonic acid(TES), 2-(N-morpholino)ethanesulfonic acid (YMS),N-(carbamoylmethyl)iminodiacetic acid (ADA),N-(2-acetamido)-2-aminoethanesulfonic acid (ACES), bis tris propane,piperazine-N,N′-bis(2-ethanesulfonic acid)(PIPES),N-(2-acetamido)-2-aminoethanesulfonic acid (ACES),3-morpholino-2-hydroxypropanesulfonic acid (MOPSO), cholamine chloride,(3-(N-morpholino)propanesulfonic acid) (MOPS),N,N-bis(2-hydroxyethyl)taurine (BES),N,N-bis(2-hydroxyethyl)-3-amino-2-hydroxypropanesulfonic acid (DIPSO),4-(N-morpholino)butanesulfonic acid (MOBS),3-[N-rris(hydroxymethyl)methylamino]-2-hydroxypropanesulfonic acid(TAPSO), acetamidoglycine, triethanolamine (TEA),piperazine-N,N′-bis(2-hydroxypropanesulfonic acid) POPSO,4-(2-hydroxyethyl)piperazine-1-(2-hydroxypropanesulfonic acid) hydrate(HEPPSO), 3-[4-(2-hydroxyethyl)-1-piperazinyl]propanesulfonic acid(HEPPS), tricine, tris(hydroxymethyl)aminomethane, trometamol (TRIZMA),glycinamide, glycyl-glycine,N-(2-hydroxyethyl)piperazine-N′-(4-butanesulfonic acid) (HEPBS), bicine,2-amino-2-methyl-1-propanol (AMP),N-(1,1-dimethyl-2-hydroxyethyl)-3-amino-2-hydroxypropanesulfonic acid(AMPSO), N-cyclohexyl-2-hydroxyl-3-aminopropanesulfonic acid (CAPSO),N-cyclohexyl-3-aminopropanesulfonic acid (CAPS),4-(cyclohexylamino)-1-butanesulfonic acid (CABS), and(4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid) (HEPES), carnitine,gamma-aminobutyric acid, taurine, or salts of amino acids alanine,arginine, asparagine, aspartic acid, cysteine, glutamic acid, glutamine,glycine, histidine, isoleucine, leucine, lysine, methionine,phenylalanine, proline, serine, threonine, tryptophan, tyrosine, valine,or a combination thereof.
 14. The apparatus of claim 2, wherein thesample area comprises a residual sample area buffer composition, andwherein the residual sample area buffer composition comprises apotassium salt of a weak acid and at least one surfactant.
 15. Theapparatus of claim 2, wherein the conjugate area comprises a residualconjugate area buffer composition, and wherein the residual conjugatearea buffer composition comprises a Good's buffer salt and one or moreof a protein, an oligomer, a polymer, and a surfactant.
 16. Theapparatus of claim 2, wherein the detection area comprises a residualdetection area buffer composition, and wherein the residual detectionarea buffer composition comprises a phosphate salt and one or more of asaccharide, a protein, an oligomer, and a polymer.
 17. The apparatus ofclaim 1, wherein the lateral flow assay is configured to detect multipleanalytes.
 18. The apparatus of claim 2, wherein the residual buffercomposition is configured to reduce the acidity of a test liquid. 19.The apparatus of claim 2, wherein the residual buffer composition isconfigured to increase the viscosity of a test liquid.
 20. The apparatusof claim 2, wherein the residual buffer composition is configured tosubstantially reduce or substantially remove the appearance of coloredcomponents of a test liquid.
 21. A method of detecting an analyte in aliquid, said method comprising: providing the apparatus of claim 1;exposing a portion of the apparatus to the liquid; and observing anindication to determine presence or absence of the analyte in theliquid.
 22. The method of claim 21, wherein the liquid is a beverage.23. The method of claim 21, wherein the liquid is a food extract. 24.The method of claim 21, wherein the liquid has a pH from about 4.5 toabout 6.8.
 25. A method of making an apparatus for detecting thepresence of an analyte in a liquid, the method comprising: applying abuffer solution to at least one of a conjugate area; a detection area;or a sample area for receiving a liquid; drying the buffer solution;applying at least one anti-analyte antibody-particle conjugate oranti-analyte aptamer-particle conjugate to at least a portion of theconjugate area; applying at least one analyte-conjugate protein to atleast a portion of the detection area; and assembling the conjugate pad,detection area, sample area and a wick so that the sample area is incontact with a portion of the conjugate area, another portion of theconjugate area is in contact with a proximal end of the detection area,and the wick is in contact with a distal end of the detection area.